GB2440752A

GB2440752A - Water pipe and water meter monitoring system

Info

Publication number: GB2440752A
Application number: GB0621135A
Authority: GB
Inventors: Douglas Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-08-09
Filing date: 2006-10-23
Publication date: 2008-02-13
Also published as: GB0621135D0

Abstract

A water pipe and water meter monitoring system comprises a length of exposed electrical conducting material (G) inside a length of water pipe (H), a 'volts free' magnetic reed relay switch (N), an earthing rod (O) and a monitoring unit (C). The system may be used to detect a leak of water from the pipe (H) by monitoring changes in earth loop electrical resistance when water leaks from the pipe and makes contact with the ground (M). The system may be used to provide remote water meter monitoring using the magnetic reed relay switch. The remote meter (I) has magnetic elements which move with the flow of water and which opens and closes the relay switch (N) which is connected to an electrical earth and provides earth loop electrical resistance variations which are monitored in unit (C). The system may also comprise an exposed electrical conducting material (G) with linear electrical resistance properties and a length of an electrically insulated electric conductor (E) inside the pipe (H) which are used to detect water leak location along the pipe. The earth loop resistance variations are monitored and the leak position is calculated from the resistance changes. The exposed electrical conducting surface (G) inside the pipe can also be used as a communications bearer for a variety of remote signalling applications.

Description

-1-2440752 WATER PIPE AND WATER METER MONITORiNG SYSTEM This invention

relates to a water pipe and water meter monitoring system.

All water utility companies are installing, or have installed, water meters for all users of water.

In some instances water meters are remotely located from the premises using the water, especially for users in rural environments.

For example, in rural environments remote water meters are usually installed in the ground adjacent to a road on public ground and bordering the premises to be served with the service pipe running a relatively long distance underground before entering the premises. Access to the water meter for reading the meter and turning offYon the supply is usually via a small metal cover. This remoteness of the water meter means that it is inconvenient for water users to physically check their water meters to cariy out simple tests to check for water leaks.

Even though water meters have a facility that can provide a volts free' contact closure each time a unit value of water passes through the water meter (typically I litre), it is often impractical to utilise this facility for automatic water leak detection and/or remote water meter monitoring purposes because the remote location of the water meter often means that no electrical power is available and because of the exposed nature of the location it is impractical to utilise solar power, wind power or lay cables to provide electrical supplies. The use of either wireless (radio transmitters, cellular radio, optical links, etc.) or cables for remote water leak detection signalling purposes is also often impractical. This said, products do exist that use battery power and wireless communications, but they are often limited in their application Once water leaks are detected in service pipes it is often difficult to exactly locate where the leak has occurred for the purpose of repair. This is especially the case, for example, if the water leak is relatively small, the length of the service pipe is long and the terrain in which the service pipe is laid underground has good drainage. Even though a number of equipment types exist to locate leaks in service pipes the use of such equipment is sometimes prohibitive or impractical for a number of reasons.

Also, most water utility companies are installing, or have installed, smart' water meters that can provide remote meter readings and water usage, especially in new build properties in urban environments where bearer circuits are available to provide remote signalling.

Although equipment is available to identif if a water leak is occurring in a user's premises there are few systems that automatically identify when water leaks occur in a water utility's mains water pipes. In most cases major water leaks are easily identified and mostly reported by members of the public. However, small leaks can go undetected for a number of reasons thus wasting a valuable resource.

The water pipe and water meter monitoring system herein described dispenses with the need to use wireless or cables or the need for local electricity supplies at remote water meter installations for the purpose of water leak detection and remote water meter monitoring. The water pipe and water meter monitoring system herein described also dispenses with the need to utilise water leak location detection equipment for the purpose of locating a water leak in a service pipe.

The water pipe and water meter monitoring system herein described can also be used to notify water utility companies, via a smart' water meter's remote signalling capability, when a water leak is detected in the water main supplying the water user's premises. The water pipe and water meter monitoring system herein described can also be used to notify water utility companies, via a smart' water meter's remote signalling capability, when a water leak is detected and the location of the water leak in the water main supplying the water user's premises.

For the purpose of water leak detection, the water pipe and water meter monitoring system herein described utilises an exposed electrical conducting surface inside and along the whole length of the water user's service pipe and a monitoring unit installed in an appropriate location within the water user's premises.

For the purpose of remote water meter monitoring, the water pipe and water meter monitoring system herein described utilises an exposed electrical conducting surface inside and along the whole length of the water user's service pipe, a magnetic volts free reed relay switch and earthiag rod installed at the remote water meter location and a monitoring unit installed in an appropriate location within the water user's premises.

For the purpose of water leak location detection, the water pipe and water meter monitoring system herein described utilises an exposed electrical conducting surface providing linear electrical resistance characteristics inside and along the whole length of the water user's service pipe, an insulated electrical conductor inside and along the whole length of the water user's service pipe and a monitoring unit installed in an appropriate location within the water user's premises.

For the purpose of water leak detection in the water utility company's mains water pipe supplying the water user's smart' metered premises, the water pipe and water meter monitoring system herein described utilises an exposed electrical conducting surface inside and along a specified length of the water utility company's mains water pipe and a monitoring unit installed in an appropriate location for connection to the smart' water meter located in the water user's premises.

For the purpose of water leak location detection in the water utility company's mains water pipe supplying the water user's smart' metered premises, the water pipe and water meter monitoring system herein described utilises an exposed electrical conducting surface providing linear electrical resistance characteristics inside and along a specified length of the water utility company's mains water pipe and a monitoring unit installed in an appropriate location within the water user's premises.

A detailed description of the water pipe and water meter monitoring system invention for the purpose of water leak detection is provided using reference to the drawings in figure 1 of page 1/6 and Figure 2 of page 2/6.

A detailed description of the water pipe and water meter monitoring system invention for the purpose of remote water meter monitoring is provided using reference to the drawings in figure 3 of page 3/6 and Figure 4 of page 4/6.

A detailed description of the water pipe and water meter monitoring system invention for the purpose of water leak location detection is provided using reference to the drawings in figure 5 of page 5/6 and Figure 6 of page 5/6.

A detailed description of the water pipe and water meter monitoring system invention for the purpose of water leak detection and water leak location detection in a water utility company's mains water pipe is provided using reference to previous detailed descriptions.

Figure 1 of page 2/6 shows the water supply system for a typical existing water user from the user's internal water supply stopcock A to the water utility's mains distribution pipe L. Located in the water user's building are a stopcock A, a water service pipe cable entry/exit point B and a monitoring unit C. Connecting the water user's stopcock A to the remote water meter I is a service pipe H buried in the ground M. Located in a hole in the ground M and accessed via a service hatch is a remote water meter I and a stopcock J. Water is fed from the water utility's mains distribution pipe L into the water meter IviapipeK.

Inserted into the service pipe H, via the service pipe entiy/exit point B, is an electrical cable F with an electrically insulated and waterproof covering E and an exposed electrical conducting surface G. The electrical cable F is inserted as far as the remote water meter I with the electrical conducting surface 0 being exposed along the whole length of the service pipe H between the remote water meter land a point exterior to the outside wall D of the water user's building where stopcock A is located. The electrical cable F is connected to a monitoring unit C. The electrical cable F is made from material that exhibits acceptable electrical conductivity, electrical waterproof insulation (where required) and adequate tensile strength to enable the cable to navigate bends in the service pipe H when inserted by suitable means and pushed the required distance along the interior of the service pipe H from the service pipe entry/exit point B. For example, Nylon insulated (where required) single strand medium hard stainless steel wire.

The basic principle used by the water pipe and water meter monitoring system invention is that the electrical resistance of water supplied by water utility companies is electronically measurable with the electrical resistance vaiying dependent on the water's purity and mineral content. For example, distilled water is a very good electrical insulator, whereas salt water is a good electricity conductor.

This principle, combined with the high probability that most water service pipes are made from materials that do not conduct electricity and that remote water meters and stopcocks are physically supported away from the ground means that under normal conditions (no water leaks) the water contained in the service pipe H is electrically insulated from the ground M except at points where metal water pipes within the user's building are electrically earthed (safety requirement) and where water within the water utility's mains distribution pipe L makes contact with the ground M. This means that if a water leak was to occur anywhere along theservice pipe H the water seeping out of the service pipe H into the ground M would electrically earth the water within the service pipe H at the location of the leak.

The reason for the electrical cable F having an electrically insulated and waterproof covering E inside service pipe H from the cable entry/exit point B to just beyond the outside wall D of the water user's building, is to ensure that high electrical resistance exists under normal water supply conditions between the exposed electrical conducting surface G of the electrical cable F and where the water in the service pipe H is electrically earthed inside the user's building. This high electrical resistance is required so that electrical resistance changes caused by water seeping out of the service pipe H into the ground M can be electronically detected by the monitoring unit C. An electrical circuit representation of the water pipe and water meter monitoring system for the purposes of water leak detections is shown in figure 2 of page 2/6.

The resistor Ri represents the electrical resistance of the water in the service pipe H from the electrical conducting surface G of the electrical cable F (as shown in figure 1 on page 1/6) and where the water is electrically earthed inside the water user's building.

The resistor R2 represents the electrical resistance of the water in contact with the electrical conducting surface G of the electrical cable F and where the water in the water utility's mains distribution pipe L (as shown in figure 1 on page 1/6) becomes electrically earthed.

The variable resistor RV1 represents the electrical resistance of the water contained within the service pipe H between the electrical conducting surface 0 of the electrical cable F and the ground M surrounding the of exterior the service pipe H (as shown in figure 1 on page 1/6).

The monitoring unit C is connected to the junction of resistor's Ri, R2 and RV1, representing the electrical conducting surface G of the electrical cable F located inside the service pipe H (as shown in figure 1 on page 1/6). The monitoring unit C is also connected to the electrical earth of the water user's electricity supply, representing the ground M (as shown in figure 1 on page 1/6).

Under nonnal water supply conditions the electrical resistance ofRVl can be considered to be very high because of the electrical insulation properties of the service pipe Ii Therefore, the electrical resistance monitored by the monitoring unit C is effectively that ofRi in parallel with R2, represented by the simple Ohm's law formula: Measured resistance (Ohms) = RI x R2 Ri +R2 However, when water leaks out of the service pipe H into the ground M, as shown in figure 1 on page 1/6, the electrical resistance of RV1 will decrease causing the electrical resistance being monitored by the monitoring unit C to also decrease. The decrease in electrical resistance monitored by the monitoring unit C can be represented by the simple Ohm's law formula: Measured resistance (Ohms) RI x R2 x RV1 R1+R2+RV1 A detailed description of the water pipe and water meter monitoring system invention for the purpose of remote water meter monitoring is hereby provided using reference to the drawings in figure 3 of page 3/6 and Figure 4 of page 4/6.

Figure 3 shows the same water supply system for an existing water user as that shown in figure 1 of page 1/6 with the addition of a volts free' magnetic reed relay switch N and an earthing rod 0 at the remote water meter I installation.

As practically all water meters utilise a metal cased measuring chamber that is both in contact with the water flowing through the meter as well as being exposed externally to the meter, an electrical contact exists from outside the meter to the water flowing inside the meter. Also, as practically all remote water meters are physically supported using water pipes made from materials that do not conduct electricity, they are electrically insulated from the ground.

For remote meter reading and monitoring applications, water meters incorporate a small permanent magnet on the analogue flow meter needle that can be used to close the contacts of a volts free' magnetic reed relay switch each time the flow meter needle makes one rotation, normally representing one litre of water flow.

The water pipe and water meter monitoring system invention uses this facility to remotely detect electrical resistance variations each time the analogue flow meter needle makes one rotation by connecting one end of the volts free' magnetic reed relay switch N to the metallic case of the water meter I and the other end of the volts free' magnetic reed relay switch N to the earthing rod 0, such that each time the volts free' magnetic reed relay switch N closes the remote water meter I becomes momentarily electrically earthed, as does the water flowing through the remote water meter I. The electrical conducting surface G of the electrical cable F is sufficiently located far enough along the service pipe H such that the electrical resistance of the water in the service pipe H to the point at which the water in the remote water meter I becomes momentarily electrically earthed by the action of the volts free' magnetic reed relay switch N and the earthing rod 0 can be electronically detected by the monitoring unit C. An electrical circuit representation of the water pipe and water meter monitoring system for the purpose of remote water meter monitoring is shown in figure 4 of page 4/6.

The resistor Ri represents the electrical resistance of the water in the service pipe H from the electrical conducting surface G of the electrical cable F (as shown in figure 3 on page 3/6) and where the water is electrically earthed inside the water user's premises.

The resistor 1(2 represents the electrical resistance of the water in the service pipe H from the electrical conducting surface G of the electrical cable F and where the water makes electrical contact with the metal measuring chamber of the remote water meter I (as shown in figure 3 on page 3/6). The resistor R3 represents the electrical resistance of the water between the metal measuring chamber of the remote water meter I and a point where the water in the water company's mains distribution pipe L (as shown in figure 3 on page 3/6) becomes electrically earthed.

The switch SWI represents the volts free' magnetic reed relay switch N that is electrically connected to the metal measuring chamber of the remote water meter I and the earthing rod 0 (as shown in figure 3 on page 3/6). The monitoring unit C is connected to the junction of resistor's Ri and 1(2, representing the electrical conducting surface G of the electrical cable F located inside the water service pipe H (as shown in figure 3 on page 3/6). The monitoring unit C is also connected to the electrical earth of the water user's electricity supply, representing the ground M (as shown in figure 3 of page 3/6).

When SW1 is open the electrical resistance being electronically measured by the monitoring unit C, is that of RI in parallel with R2 pIus 1(3, represented by the simple Ohm's law formula: Measured resistance (Ohms) = RI x (R2 + R3) RI +R2+R3 When SWI is closed the electrical resistance being electronically measured by the monitoring unit C, is that of Ri in parallel with 1(2 represented by the simple Ohm's law formula: Measured resistance (Ohms) RI x R2 Ri +R2 The electrical resistance when SW1 is open is greater than when SWI is closed.

The monitormg unit C detects, by using suitable electronic means, when the electrical earth loop resistance being measured suddenly changes caused by the opening and closing of SW1. The remote detection of SW1 opening and closing can be used for a variety of remote water meter monitoring applications such as remote meter reading, remote water flow indication and remote water leak detection.

A detailed description of the water pipe and water meter monitoring system invention for the purpose of water leak location detection is hereby provided using reference to the drawings in figure 5 of page 5/6 and Figure 6 of page 6/6.

Figure 5 of page 5/6 shows the same water supply system for an existing water user as that shown in figure 1 of page 1/6 with the difference that the electrical cable F has been replaced with an insulated single core cable F with an electrical conductive coating G on the exterior of the insulated single core cable F and with the single core conductor P of the single core cable F exposed to the water in the service pipe H at the end of the cable nearest to the remote water meter I. The electrical conductive coating G on the exterior of the insulated single core cable F is such that it provides a uniform electrical resistance of medium value between its ends, for example, by means of using a carbon film coating or other suitable electrical resistance coatings..

Alternatively, the uniform electrical resistance between the ends of the electrical conductive coating G on the exterior of the insulated single core cable F could be provided by means of a series of relatively small uniform sections of low electrical resistance conductive coatings insulated from each other at their section ends by a short gap in the coating, which when covered in water provides a uniform electrical resistance between adjacent section ends and therefore a uniform electrical resistance between the ends of the multiple sectioned electrical conductive coating G. An electrical circuit representation of the water pipe and water meter monitoring system for the purposes of water leak location detection is shown in figure 6 of page 6/6.

The resistor RI represents the electrical resistance of the water in the service pipe H from the electrical conducting coating Cl of the electrical cable F (as shown in figure 5 on page 5/6) and where the water is electrically earthed inside the water user's building.

The resistor R2A and R2B represents the uniform electrical resistance between the ends of the electrical conductive coating G on the exterior of the insulated single core cable F (as shown in figure 5 on page 5/6). Even though R2A and R2B is in effect one resistor they are shown as two resistors for the purpose of describing how a water leak is located.

The resistor R3 represents the electrical resistance of the water in contact with the single core exposed conductor P of the insulated single core cable F and with the electrical conducting coating G of the electrical cable F and where the water in the water utility's mains distribution pipe L (as shown in figure 5 on page 5/6) becomes electrically earthed.

The variable resistor RV1 represents the electrical resistance of the water contained within the service pipe H between the electrical conducting coating 0 of the electrical cable F and the ground M surrounding the of exterior the service pipe H (as shown in figure 5 on page 5/6). RVI is shown connected to the junction of R2A and R2B for the purpose of describing how a water leak is located.

The monitoring unit C is connected to point A representing the single core electrical conductor of the electrical cable F and to Point B representing the electrical conducting surface G of the electrical cable F (as shown in figure 5 of page 5/6). The monitoring unit C is also connected to the electrical earth of the water user's electricity supply, representing the ground M (as shown in figure 5 of page 5/6).

Under normal water supply conditions the electrical resistance of RVI can be considered to be very high because of the electrical insulation properties of the service pipe H (as shown in figure of page 5/6). Therefore, the electrical resistance monitored by the monitoring unit C at Point A is effectively that of R3 in parallel with R2B + R2A + Ri, represented by the simple Ohm's law formula: AMeasuredresistance(Ohms) = R3x(R2B+R2A+Ri) R3 + R2B + R2A + Ri The electrical resistance monitored by the monitoring unit C at Point B is effectively that ofRi in parallel with R2A + R2B + R3, represented by the simple Ohm's law formula: B Measured resistance (Ohms) = RI x (R2A + R2B + R3) Ri +R2A+RiB+R3 However, when water leaks out of the service pipe H into the ground M (as shown in figures on page 5/6) the electrical resistance of RV1 will decrease causing the electrical resistance being monitored by the monitoring unit C at both points A and B to also decrease.

The decrease in electrical resistance monitored by the monitoring unit C at Point A can be represented by the Ohm's law formula: A Measured resistance (Ohms) = R3 x (R2B + Rx) R3 + R2B + Rx Where Rx = RVI x (R2A Ri) RVI +RiA+Rl The decrease in electrical resistance monitored by the monitoring unit C at Point B can be represented by the Ohm's law formula: B Measured resistance (Ohms) Ri x (R2A + Rv) RI +R2B+ Ry Where Ry = RVI x (R2B + R.3) RVI +RiB+R3 The only electrical resistance difference between Point A and Point B measurements is that caused by the electrical resistance differences of R2A and R2B as the electrical resistance value ofRVl remains the same for both measurements.

As the electrical resistance value of R2A and R2B represents the uniform electrical resistance between the ends of the electrical conducting surface G of the electrical cable F (as shown on figures of page 5/6) the distance along the conducting surface G of the electrical cable F at the location where the water leak has occurred can be electronically calculated by a number means, one example being the following electronic calculation process.

Under normal conditions the electrical resistance at Point A and Point B is periodically measured and recorded electronically for reference purposes using a 40,000 Ohms (average value ofRVl under water leak conditions) resistor momentarily connected across Point B and Earth.

The electrical resistance measured at Point B represents a water leak located at the start of the service pipe and the electrical resistance measured at Point A represents a water leak located at the end of the service pipe.

Using these two electrical resistance measurements as an electronic reference the approximate electrical resistance per unit length of service pipe can be electronically calculated by subtracting the electrical resistance measured at Point B from the electrical resistance measured at Point A and dividing the result by the length of the service pipe, for example, by using the following simple formula.

Electrical Resistance per metre (m) = Resistance A -Resistance B Length of seivice pipe in metres (m) As soon as a water leak is detected, the electronic reference electrical resistance measured at Point B is subtracted from the actual electrical resistance measured at Point B and the result divided by the calculated unit length electrical resistance of the service pipe. The number electronically calculated is the distance, in unit length measurements, along the service pipe from the start of the service pipe in the water user's premises. The following formula can be used for this electronic calculation.

Leak Distance (in) from User's Premises = Actual Resistance B -Reference Resistance B Electrical Resistance per metre (m) Providing the linear electrical resistance of the conducting surface G of electric cable F (as shown in figure 5 of page 5/6) is relatively low (for example 1,000 Ohms per meter) and the electrical resistance ofRi and R3 is relatively high (for example around 200,000 Ohms) the accuracy of the leak location calculation can be around +1-5% of the figure calculated.

A detailed description of the water pipe and water meter monitoring system invention for the purpose of water leak detection in a water utility company's mains water pipe is hereby provided

using reference to previous detailed descriptions.

The only differences between the water meter monitoring system invention for the purpose of water leak detection and water leak location detection in a water utility company's mains water pipe and water meter monitoring system invention for the purpose of water leak detection and water leak location detection in a water user's service pipe is that the exposed electrical conducting surface is inside water utility company's mains water pipe instead of along the whole length of the water user's service pipe.

Also, the monitoring unit is installed in an appropriate location to connect to the smart' water meter in the water user's premises for the purposes of signalling a water leak alarm and/or leak location information back to the water utility company.

Even though the electrical resistances characteristics will change in the service pipe and/or the water utility's mains water pipe caused by a variety of factors, for example, water temperature, purity, mineral content, water pressure as well as earth circuit continuity, these changes are expected to be gradual and will not valy significantly. However, resistance changes caused by water leaks and earth loop signalling at remote water meters will be significant and occur relatively quickly.

The electric conducting material with an exposed electrical conducting surface, with and without linear electrical resistance properties as previously described for water leak detection and/or remote water meter monitoring and/or water leak location detection, provided in a suitable material form and construction, can be inserted in a water pipe and extracted from a water pipe to provide a communications bearer circuit for a number of remote signalling applications on existing water pipe installations.

The electric conducting material with an exposed or insulated electrical conducting surface, with and without linear electrical resistance properties as previously described for water leak detection and/or remote water meter monitoring and/or water leak location detection, provided as part of the manufacturing process used to produce water pipes can be used as a communications bearer circuit for a number of remotesignalling applications on new or replacement water pipe installations.

The detailed description of the water pipe and water meter monitoring system invention herein provided relates to a field installed system to an existing remote water meter and service pipe installation or a water utility's mains water pipe installation.

The same water pipe and water meter monitoring system description also applies to new remote water meter installations or new water utility's mains water pipe installations using water pipes manufactured with either an exposed electiical conducting surface or manufactured with an exposed linear electrical resistance conducting surface and insulated conductor inside the pipe.

The same description also applies to new remote water meter installations or new water utility's mains water pipe installations using water pipes with cables having an electrical conducting surface or an exposed linear electrical resistance conducting surface and insulated conductor that are inserted at time of water pipe installation.

Claims

-13 -

CLAIMS

1. The water pipe and water meter monitoring system comprising a length of electric conducting material and a monitoring unit provides water pipe leak detection.

2. The water pipe and water meter monitoring system comprising a length of conducting material, a magnetic volts free reed relay switch, an earthing rod and a monitoring unit provides remote water meter monitoring.

3. The water pipe and water meter monitoring system comprising a length of electric conducting material with linear electrical resistance properties, a length of an electrically insulated electric conductor and a monitoring unit provides water leak location detection.

4. A length of electric conducting material, as claimed in Claim 1 and Claim 2, with an exposed electrical conducting surface located inside a water user's service pipe provides an electrical conductor that is in contact with the water contained along the required length of the water user's service pipe.

5. A length of electric conducting material, as claimed in Claim 1 and Claim 2, with an exposed electrical conducting surface located inside a water utility's mains water pipe, provides an electrical conductor that is in contact with the water contained along the required length of the mains water pipe.

6. A length of electric conducting material, as claimed in Claim 3, with an exposed electrical conducting surface with linear electrical resistance properties and a length of an electrically insulated electric conductor with an exposed electrical conducting surface at one end located inside a water user's service pipe provides an electrical conductor that is in contact with the water contained along the required length of the water user's service pipe and an electric conductor that is in contact with the water at one end of the required length of the water user's service pipe.

7. A length of electric conducting material, as claimed in Claim 3, with an exposed electrical conducting surface with linear electrical resistance properties and a length of an electrically insulated electric conductor with an exposed electrical conducting surface at one end located inside a water utility's mains water pipe provides an electrical conductor that is in contact with the water contained along the required length of the water utility's mains water pipe and -14 -an electric conductor that is in contact with the water at one end of the required length of the water utility's mains water pipe.

8. A length of exposed electric conducting material, as claimed in Claim 1, Claim 2 and Claim 3, with a suitable length of electrical and waterproof rnsulation provides high electrical resistance between the metal water piping of the water user's premises and the exposed electrical conducting surfIce of the electric conducting material in the water pipes, as claimed in Claim 4, Claim 5, Claim 6 and Claim 7.

9. A monitoring unit, as claimed in Claim I, suitably located and electrically connected to a length of electric conducting material, as claimed in Claim 4 and Claim 8, detects earth loop electrical resistance variations when water leaks from a water user's service pipe and makes contact with the ground surrounding the water user's service pipe.

10. A monitoring unit, as claimed in Claim 1, suitably located and electrically connected to a length of electric conducting material, as claimed in Claim 5 and Claim 8, detects earth loop electrical resistance variations when water leaks from a water utility's mains water pipe and makes contact with the ground surrounding the water utility's mains water pipe.

11. A monitoring unit, as claimed in Claim 2, suitably located and electrically connected to a length of electric conducting material, as claimed in Claim 4 and ClaimS, detects earth loop electrical resistance variations when an electrical switch connected to an electrical earth and activated by a co-located water meter opens and closes.

12. A monitoring unit, as claimed in Claim 3, suitably located and electrically connected to a length of exposed electrical conducting material with linear electrical resistance properties and a length of electrically insulated electric conductor with an exposed electrical conducting surface at one end, as claimed in Claim 6 and Claim 8, detects earth loop electrical resistance variations when water leaks from a water user's service pipe and uses these electrical resistance variations to electronically calculate the location of the water leak 13. A monitoring unit, as claimed in Claim 3, suitably located and electrically connected to a length of exposed electrical conducting material with linear electrical resistance pToperties and a length of electrically insulated electric conductor with an exposed electrical conducting surface at one end, as claimed in Claim 7 and Claim 8, detects earth loop electrical resistance variations when water leaks from a water utility's mains water pipe and uses these electrical resistance variations to electronically calculate the location of the water leak.

-15 - 14. The exposed electric conducting material as claimed in Claim 1, Claim 2, Claim 4 and Claim 5, can be a suitably constructed material inserted into water pipes for existing installations or provided as part of the manufacturing process used to produce water pipes that could be used for new or replacement installations.

15. The electric conducting material with an exposed electrical conducting surface with linear electrical resistance properties and a length of an electrically insulated electric conductor, as claimed in Claim 3, Claim 6 and Claim 7, can be a suitably constructed material inserted into the water pipe for existing installations or provided as part of the manufacturing process used to produce water pipes that could be used for new or replacement water pipe installations.

16. The electric conducting material with an exposed electrical conducting surface, with and without linear electrical resistance properties as claimed in Claim 1, Claim 2, Claim 3, Claim 4, Claim 5, Claim 6, Claim 7 and Claim 8, provided in a suitable material form and construction, can be inserted in a water pipe and extracted from a water pipe to provide a communications bearer circuit for a number of remote signalling applications on existing water pipe installations.

17. The electric conducting material with an exposed or insulated electrical conducting surface, with and without linear electrical resistance properties, provided as part of the manufacturing process used to produce water pipes as claimed in Claim 14 and Claim 15, can be used as a communications bearer circuit for a number of remote signalling applications on new or replacement water pipe installations.