GB2461607A

GB2461607A - Sensing water level in gutters based on measured variation in resistance between two electrodes

Info

Publication number: GB2461607A
Application number: GB0907655A
Authority: GB
Inventors: Timothy Charles Hutton
Original assignee: Hutton & Rostron Environmental
Current assignee: Hutton & Rostron Environmental
Priority date: 2009-05-05
Filing date: 2009-05-05
Publication date: 2010-01-13
Anticipated expiration: 2029-05-05
Also published as: GB2461607B; GB0907655D0

Abstract

A gutter water level sensor 10 comprises a main body 6a,6b having an outer wall which defines a chamber 7. First 1a and a second 1b electrodes are located within the chamber and separated from each other. The electrodes are substantially sheltered from water falling onto the outer wall of the main body. Water can rise up into the chamber 7 though an inlet at its lower end to provide a conduction path between the electrodes. The inlet may be covered with a grille or mesh (8, fig.3) which prevents detritus from entering the chamber. Air vents 9 allow air to enter or leave the chamber 7, but they are angled to reduce the risk of rainwater entering. The electrodes may be insulated from each other by a block 4 of hydrophobic material. A monitoring system connected to one or more such sensors issues an alarm based on a comparison of the electrical resistance of the sensor with a predetermined threshold.

Description

A Gutter Water Level Sensor Arrangement The present invention relates to a gutter water level sensor arrangement, a monitoring system, and a building including a gutter water level sensor arrangement.

Rainwater can damage delicate or vulnerable materials used in the construction of many buildings. Prolonged exposure to rainwater can, for example, cause many building materials to rot or suffer water damage.

Rainwater which falls on the roof of a building is typically carried away from the building through a roof rainwater drainage system. Such systems typically include one or more gutters.

Gutters which are part of roof rainwater drainage systems frequently become blocked, partially blocked, or overcharged. This may cause water to overflow from the gutter into or onto the building causing damage or decay to vulnerable materials.

Parts of roof rainwater drainage systems which are at risk from blockage, partial blockage or overcharging are frequently relatively inaccessible for inspection and maintenance. Some parts of roof rainwater drainage systems will only overflow during bad weather -making detection even more difficult.

Undetected rainwater damage can be serious and may only be detected when the damage is considerable (and potentially expensive to repair).

The problems associated with undetected rainwater damage are particularly significant in historic buildings with complex and relatively inaccessible roof rainwater drainage systems, in unoccupied buildings or in buildings with reduced or intermittent occupancy. Buildings with multiple occupancy with no clear responsibility for day to day inspection and maintenance are also at risk.

The present invention seeks to ameliorate the problems associated with undetected overflowing gutters.

Accordingly, one aspect of the present invention provides a gutter water level sensor arrangement comprising: a main body having an outer wall and defining a chamber and an inlet flow path allowing fluid communication between the chamber and the exterior of the main body; and a first and a second electrode located at least partially within the chamber and separated from each other such that, in a use orientation, the electrodes are substantially sheltered from water falling onto the outer wall of the main body and water can rise into the chamber through the inlet flow path to provide a conduction path between the first and the second electrodes.

Preferably, the second electrode is tubular and surrounds the first electrode.

Advantageously, one or more vents are provided through an entire depth of the main body, the or each vent being angled with respect to a central longitudinal axis of the gutter water level sensor arrangement such that an outer aperture of the or each vent is closer to an end of the chamber remote from the electrodes than the inner aperture.

Conveniently, at least part of the first electrode is separated from at least part of the second electrode by an insulating block of hydrophobic material.

Preferably, the inlet flow path of the chamber is covered by a mesh or grille.

Advantageously, the main body is constructed out of a hydrophobic material.

Preferably, the gutter water level sensor arrangement further comprises one or more resistors connected in series with the first and second electrodes.

Conveniently, the gutter water level sensor is fitted to a gutter.

Alternatively, the gutter water level sensor is fitted to a drain.

Another aspect of the present invention provides a monitoring system connected to a gutter water level sensor arrangement.

Preferably, the system is configured to determine the electrical resistance between the electrodes of the gutter water level sensor arrangement and to issue an alarm if the determined electrical resistance falls below a predetermined threshold electrical resistance.

Conveniently, the monitoring system further comprises an adjustment arrangement for adjusting the predetermined threshold electrical resistance.

Advantageously, the predetermined threshold electrical resistance is between approximately 100k Ohms and 1 OOM Ohms.

Preferably, the system is configured to issue an alarm over a network.

Another aspect of the present invention provides, a monitoring system connected to one or more gutter water level sensors, wherein the electrical resistance of the or each gutter water level sensor varies dependent on a water level at the respective sensor and the monitoring system is configured to determine the electrical resistance of the or each gutter water level sensor and compare the determined electrical resistance with a predetermined threshold electrical resistance for that gutter water level sensor.

Preferably, the system is connected to a plurality of gutter water level sensors and the predetermined threshold electrical resistance for each gutter water level sensor is independently adjustable with respect to the predetermined threshold electrical resistance for the or each other gutter water level sensor.

Advantageously, the system is connected to one or more gutter water level sensors.

Another aspect of the present invention provides a building including a gutter water level sensor arrangement.

Preferably, the building further comprises a monitoring system.

Embodiments of the present invention are described herein by way of example with reference to the accompanying figures in which: Figure 1 shows a gutter water level sensor arrangement in accordance with an embodiment of the present invention; Figure 2 shows a cross-sectional view of a gutter water level sensor arrangement in accordance with an embodiment of the present invention; Figure 3 shows a an end view of a gutter water level sensor arrangement in accordance with an embodiment of the present invention; Figure 4 shows a cross-sectional view of a gutter water level sensor arrangement in accordance with an embodiment of the present invention through line B-B as shown in figure 2; Figure 5 shows a schematic view of a gutter water level sensor arrangement fitted to a gutter of a roof rainwater drainage system; and Figure 6 shows a schematic view of a monitoring system and gutter water level sensor.

A gutter water level sensor arrangement 10 in accordance with an embodiment of the present invention is shown in figure 1.

The gutter water level sensor arrangement 10 comprises a main body 6. In an embodiment, the main body 6 comprises a first 6a and a second 6b section.

Alternatively, the main body 6 may be a single integrally formed object including both the first and second sections 6a,6b -the first and second sections define an outer wall 6c of the sensor arrangement.

The first section 6a of a main body 6 of the gutter water level sensor arrangement 10 comprises tube defining an internal cavity 11 configured to receive a cable 2 through a first end 11 a of cavity (see figure 2). The first section 6a may be generally frustoconical in external shape and the internal cavity ills preferably cylindrical in shape.

A first electrode la is located within the internal cavity 11 of the first section 6a of the main body 6 and extends towards a second end 11 b of the cavity 11 (the first end ha of the cavity 11 opposes the second end lib of the cavity 11 across a length thereof). In an embodiment, the first electrode ha is a central electrode which has a central longitudinal axis which is generally parallel with a central longitudinal axis of the internal cavity 11 of the first section 6a of the main body 6 of the gutter water level sensor arrangement 10. In an embodiment, the central longitudinal axis of the first electrode la is also aligned with the central longitudinal axis of the internal cavity 11 (i.e. the first electrode la is preferably co-axial with the internal cavity 11). The first electrode 1 a may extend beyond the second end 11 b of the cavity 11 of the first section 6a of the main body 6.

A second electrode 1 b is also located within the internal cavity 11 of the first section 6a of the main body 6 and extends towards the second end 11 b of the cavity 11. The second electrode 1 b is spaced apart from the first electrode la (see figure 4). In an embodiment, a insulating block 4 separates part of the first electrode la from part of the second electrode lb within the internal cavity 11 of the first section 6a of the main body 6. The second electrode lb may comprise a tube which surrounds at least part of the first electrode la but which is separated therefrom by a gap. As described above part of this gap between the electrodes 1 may be filled by an insulating material such as an insulating block 4. Part of the gap between the electrodes is an air gap.

The insulating block 4 is preferably constructed out of a hydrophobic material so as to prevent a thin film or coating of water or other similar material providing a conduction path between the first la and second lb electrodes.

In an embodiment, the insulating block 4 is constructed out of a hydrophobic plastic and/or has a hydrophobic coating. In an embodiment, the hydrophobic coating is a silicon based coating. In an embodiment, the insulating block 4 is an insulating member which may be in the form of an insulating sheath.

A length of the first electrode la is preferably substantially the same as a length of the second electrode lb. The central longitudinal axis of the first electrode la may be parallel with a central longitudinal axis of the second electrode lb. In an embodiment, the first electrode la is co-axial with the second electrode lb (i.e. the central longitudinal axes of the electrodes 1 are both parallel and aligned with each other).

In an embodiment (not shown), the first electrode la is substantially straight elongate electrode, and second electrode lb (which is also elongate in form) has a first part which is substantially straight (and is parallel to the first electrode la) and a second part which is curved away from an extreme remote end of the first electrode 1 a. Insulating material (which may be part of the insulating block or sheath 4) may cover the first part of the second electrode 1 b and may cover part of the second part of the second electrode 1 b. Insulating material may also cover part of the first electrode 1 a (and may also be part of the insulating block or sheath 4). In this arrangement, when positioned such that the first la and second lb electrodes extend generally downwards, any water which runs down the electrodes 1 is less likely to create a conduction path between the electrodes 1.

As will be appreciated, other electrodes arrangements are possible.

In an embodiment, one or more vents 9 are provided through an entire depth of a tubular wall of the first section 6a of the main body 6. The or each vent 9 is defined by an external aperture 9a in the tubular wall 6c of the first section 6a, an internal aperture 9b in the tubular wall 6c of the first section 6b, and a vent wall (which may be part of the tubular wall 6c of the first section 6a of the main body 6) which extends between the internal 9b and external 9a apertures.

The or each vent 9 may be a generally radial vent through the entire depth of the tubular wall 6c of the first section 6a of the main body 6. The internal 9b and external 9a apertures which define the or each vent 9 may be offset from each other such that the vent 9 is angled with respect to the central longitudinal axis of the internal cavity 11 of the first section 6a and the external aperture 9a is closer to a second end 6d of the first section 6a than a first end 6e thereof (the first end 6e of the first section 6a being adjacent the first end ha of the internal cavity 11 and the second end 6d of the first section 6a being adjacent the second end 11 b of the cavity 11).

The or each vent 9 may extend through an entire depth of part of the second electrode lb. A second section 6b of the main body 6 of the gutter water level sensor arrangement 10 is attached to the first section 6a. This attachment may be a removable attachment -for example, each section 6a,6b may carry one of a pair of corresponding threads (not shown) which are configured to mate and thus secure the first and second sections 6a,6b of the main body 6 together.

The first and second sections 6a,6b of the main body 6 may be adhered to each other or there may be press-fitted to each other.

The second section 6b comprises a tube defining a chamber 7. The chamber 7 is in fluid communication with the internal cavity 11 of the first section 6a of the main body 6. A first end 6f of the second section 6b of the main body 6 is attached to the second end 6d of the first section 6a of the main body 6. A second end 6g of the second section 6b of the main body 6 is at least partially covered by a grille or mesh 8 (see figure 3). In an embodiment, the second end 6g of the second section 6b comprises an inlet flow path which allows fluid communication between the exterior of the sensor arrangement and the chamber 7. The grille or mesh 8 allows fluid -such as rainwater -to enter and leave the chamber 7. The grille or mesh 8 helps to prevent detritus from entering the chamber 7. As will be appreciated, the mesh or grille 8 defines one or more apertures 8a and, in an embodiment, a plurality of apertures 8a.

More specifically, fluid can enter (or rise into) the chamber 7 of the second section 6b of the main body 6 through the or each aperture 8a of the mesh or grille 8. If the fluid level is sufficient then the fluid may also enter at least part of the internal cavity 11 of the first section 6a of the main body 6.

The electrodes 1 are configured relative to the main body 6 such that rainwater (for example) of a predetermined minimum level within the chamber 7 will form a conduction path between the electrodes 1.

The main body 6 may, in an embodiment, be constructed out of a hydrophobic material and which forms a shroud which helps to protect the electrodes 1 from rain, snow, ice, detritus and environmental contaminants.

In an embodiment, the main body 6 is constructed out of a hydrophobic plastic and/or has a hydrophobic coating. The hydrophobic coating may be a silicon based coating.

The or each vent 9 is in fluid communication with the chamber 7 and helps to allow air to enter and leave the chamber 7 between the electrodes 1, so as to reduce the risk of an air lock forming in the chamber 7 such that rainwater (for example) can enter and leave the chamber 7 through the or each vent 9 or through the grille or mesh 8. The orientation of the or each vent 9 reduces the risk of rainwater falling onto the gutter water level sensor arrangement 10 from entering the chamber 7 through the or each vent 9 -when the sensor arrangement is fitted to a gutter 20 -and causing a conduction path to be formed between the electrodes 1 when the water level in the gutter 20 is relatively low (see figure 5).

In an embodiment, a cable 2 is fitted to the main body 6 of the gutter water level sensor arrangement 10. The cable 2 comprises at least two conductors (not shown); one of the two conductors is connected to the first electrode la and the other is connected to the second electrode 1 b. The cable 2 may be an exterior grade electrical cable.

The electrodes 1 are preferably of a relatively corrosion resistant material and this may be nickel plated copper or stainless steel.

In an embodiment, the gutter water level sensor arrangement 10 is connected to a monitoring system 30 (see figure 6). The monitoring system 30 is preferably an automatic electronic remote monitoring and alarm system. The monitoring system 30 is capable of measuring electrical resistance between the electrodes 1 of the sensor arrangement 10 in a range of at least 100k Ohms to lOOM Ohms. In an embodiment, this measurement is made by applying a known pulsed DC or AC voltage to the electrodes 1 of the sensor arrangement 10 and measuring the current through the circuit (and calculating the resistance using Ohm's Law) or by balancing the resistance against a known resistance -for example, a Wheatstone bridge circuit could be used.

In an embodiment, the monitoring system 30 is a radio telemetric system. In an embodiment, the monitoring system 30 is configured to provide remote monitoring information regarding the gutter water level sensor arrangement via the Internet or telephone system or a radio network or other network or combination thereof.

In an embodiment, one or more resistors (not shown) are connected to the gutter water level sensor arrangement. In this embodiment, the or each resistor is connected to the sensor arrangement such that the or each resistor is in series with the electrodes 1 of the sensor arrangement 10 in an electric circuit.

In an embodiment, the or each resistor is located in the gutter water level sensor arrangement 10. In an embodiment, the or each resistor is located in the monitoring system 30. In an embodiment, the or each resistor is located along a length of the cable 2.

The or each resistor reduces the effect of short circuits to electrical earth that may be formed by the gutter or other building components under wet conditions and permit testing and calibration of the sensor arrangement when installed. The or each resistor may have a resistance between approximately 50-100k Ohms.

Thus, a gutter water level sensor arrangement 10 according to an embodiment of the present invention may be fitted to a gutter 20 of a roof rainwater drainage system 21 (see figure 5). In an embodiment, the sensor arrangement 10 is preferably fitted to the gutter 20 using a bracket, a metal clip, or a plastic clip (not shown) which couples the sensor arrangement 10 to a wall 23 of the gutter 20. In an embodiment, the sensor arrangement 10 is positioned generally above a drain of the gutter (not shown). In an embodiment, the sensor arrangement 10 is fitted to a protective cage (not shown) which may be located generally over a drain of the gutter.

The sensor arrangement 10 is oriented such that the mesh or grille 8 is adjacent a base wall 24 of the gutter 20. In an embodiment, the mesh or grille 8 is spaced apart from the base wall 24 of the gutter 20 by a predetermined distance. In an embodiment, the mesh or grille 8 includes one or more spacers (not shown) which project from the mesh or grille 8 to space the sensor arrangement 10 away from the base wall 24 of the gutter 20 by a distance which is approximately equal to a length of the or each spacer.

The sensor arrangement 10 is typically fitted to a gutter 20 such that the electrodes 1 are above the normal water level of gutter 20. The height of the electrodes 1 above the normal water level is known as an alarm level.

Rainwater falling on the sensor arrangement 10 will typically flow down the outside of the main body 6 of the arrangement 10 and enter the gutter 20.

The orientation of the or each vent 9 reduces the likelihood of rainwater falling onto the arrangement 10 from entering the chamber 7 through the vent 9.

As the gutter 20 fills with rainwater (as part of the roof rainwater drainage system 21) the water level in the gutter 20 rises. The water in the gutter 20 will flow into the chamber 7 of the sensor arrangement 10 through the mesh or grille 8. The air which was contained in the chamber 7 will usually flow out through the or each vent 9. When the rainwater level in the chamber 7 is sufficiently high, the rainwater will provide a conduction path between the electrodes 1. This occurs generally when the rainwater in the chamber 7 has reached the alarm level.

The resistance of the sensor arrangement 10 (as measured across the electrodes 1) will then drop (the rainwater in the gutter 20 having a higher conductivity than air). This drop in resistance may be monitored by the monitoring system 30 which is connected to the sensor arrangement 10. If resistance reduces to a predetermined threshold resistance, then an alarm may be triggered. This alarm may be visual or audible or both. The alarm may be transmitted telemetrically via the internet or telephone system or a radio network or other network or a combination thereof. In an embodiment, an adjustment mechanism or arrangement (not shown) is provided to allow the predetermined threshold resistance to be altered.

The alarm alerts the user to a high water level in the gutter 20 which can then be investigated to prevent or reduce the risk of water overflowing from the gutter and causing damage.

The monitoring system 30 may be connected to one or more gutter water level sensor arrangements 10 and may be configured to provide a unique alarm for each sensor arrangement 10 connected thereto -for example, the monitoring system 30 may include a control panel (not shown) with one alarm light for each sensor arrangement 10. Other sensors 31 may be connected to the monitoring system 30. The monitoring system 30 may be a special or general purpose computer programmed to perform the operations of the monitoring system 30 and connected to one or more sensor arrangements 10 -the connection may be over the internet or telephone system or radio network or other network or combination thereof.

The alarm level is preferably above the normal water level but below a water level which would be sufficient for water to overflow the gutter 20 (and perhaps cause damage to the structure of the building to which the gutter 20 is attached).

Over time corrosion, debris and the like may affect the sensor arrangement 10. The measuring of resistance (as opposed to simply noting a step change in conductance) of the sensor arrangement 10 permits the monitoring system to be calibrated to ameliorate the problems associated with false alarms and failed alarms. A sensor arrangement 10 and monitoring system 30 that simply monitors the completion of a circuit (by the rainwater providing a conduction path between a pair of electrodes) is typically prone to false alarms, or a failure to issue an alarm when one should have been issued, especially after a period of operation due to debris and corrosion around the electrodes.

The provision of a chamber 7 helps to prevent debris from building up around the electrodes during use and reduces the exposure of the electrodes to harsh environmental conditions which could otherwise cause accelerated deterioration in the electrodes (eventually resulting in failure of the sensor).

An embodiment seeks to provide a gutter water level sensor arrangement 10 which may have a lifespan (before replacement is required) of several years.

An embodiment seeks to provide a gutter water level sensor arrangement 10 which may have a lifespan of 10 years.

It will be appreciated that embodiments of the present invention include a building 40 including a gutter water level sensor arrangement 10 as described herein.

It will be understood that the gutter water level sensor arrangement 10 as described herein could be fitted to a gutter 20 or another part of a rainwater roof drainage system 21 or a drain.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

Claims: 1. A gutter water level sensor arrangement comprising: a main body having an outer wall and defining a chamber and an inlet flow path allowing fluid communication between the chamber and the exterior of the main body; and a first and a second electrode located at least partially within the chamber and separated from each other such that, in a use orientation, the electrodes are substantially sheltered from water falling onto the outer wall of the main body and water can rise into the chamber through the inlet flow path to provide a conduction path between the first and the second electrodes.
2. A gutter water level sensor arrangement according to claim 1, wherein the second electrode is tubular and surrounds the first electrode.
3. A gutter water level senor arrangement according to claim 1 or 2, wherein one or more vents are provided through an entire depth of the main body, the or each vent being angled with respect to a central longitudinal axis of the gutter water level sensor arrangement such that an outer aperture of the or each vent is closer to an end of the chamber remote from the electrodes than the inner aperture.
4. A gutter water level sensor arrangement according to any preceding claim wherein at least part of the first electrode is separated from at least part of the second electrode by an insulating block of hydrophobic material.
5. A gutter water level sensor arrangement according to any preceding claim wherein the inlet flow path of the chamber is covered by a mesh or grille.
6. A gutter water level sensor arrangement according to any preceding claim, wherein the main body is constructed out of a hydrophobic material.
7. A gutter water level sensor arrangement according to any preceding claim, further comprising one or more resistors connected in series with the first and second electrodes.
8. A gutter water level sensor arrangement according to any preceding claim, wherein the gutter water level sensor is fitted to a gutter.
9. A gutter water level sensor arrangement according to any of claims 1 to 7, wherein the gutter water level sensor is fitted to a drain.
10. A monitoring system connected to a gutter water level sensor arrangement according to any preceding claim.
11. A monitoring system according to claim 10, wherein the system is configured to determine the electrical resistance between the electrodes of the gutter water level sensor arrangement and to issue an alarm if the determined electrical resistance falls below a predetermined threshold electrical resistance.
12. A monitoring system according to claim 11, further comprising an adjustment arrangement for adjusting the predetermined threshold electrical resistance.
13. A monitoring system according to claim 11 or 12, wherein the predetermined threshold electrical resistance is between approximately 100k Ohms and lOOM Ohms.
14. A monitoring system according to any one of claims 10 to 13, wherein the system is configured to issue an alarm over a network.
15. A monitoring system connected to one or more gutter water level sensors, wherein the electrical resistance of the or each gutter water level sensor varies dependent on a water level at the respective sensor and the monitoring system is configured to determine the electrical resistance of the or each gutter water level sensor and compare the determined electrical resistance with a predetermined threshold electrical resistance for that gutter water level sensor.16. A monitoring system according to claim 15, wherein the system is connected to a plurality of gutter water level sensors and the predetermined threshold electrical resistance for each gutter water level sensor is independently adjustable with respect to the predetermined threshold electrical resistance for the or each other gutter water level sensor.15. A monitoring system according to claim 15 or 16, wherein the system is connected to one or more gutter water level sensors according to any one of claims 1 to 9.
16. A building including a gutter water level sensor arrangement according to any one of claims 1 to 9.
17. A building according to claim 16 further comprising a monitoring system according to any one of claims 8 to 15.
18. A gutter water level sensor arrangement substantially as herein before described with reference to the accompanying figures.
19. A monitoring system substantially as herein before described with reference to the accompanying figures.
20. A building substantially as herein before described with reference to the accompanying figures.
21. Any novel feature or combination of features disclosed herein.Amendments to the claims have been filed as follows: Claims: 1. A gutter water level sensor arrangement comprising: a main body having an outer wall and defining a chamber and an inlet flow path allowing fluid communication between the chamber and the exterior of the main body; and a first and a second electrode located at least partially within the chamber and separated from each other such that, in a use orientation, the electrodes are substantially sheltered from water falling onto the outer wall of the main body and water can rise into the chamber through the inlet flow path to provide a conduction path between the first and the second electrodes, wherein at least part of the first electrode is separated from at least part of the second electrode by an insulating block of hydrophobic material.2. A gutter water level senor arrangement according to claim 1, wherein one or more vents are provided through an entire depth of the main body, the (\J or each vent being angled with respect to a central longitudinal axis of the 0 gutter water level sensor arrangement such that an outer aperture of the or each vent is closer to an end of the chamber remote from the electrodes than the inner aperture, wherein the or each vent is in fluid communication with the chamber such that fluid can enter and leave the chamber between the first and second electrodes.3. A gutter water level sensor arrangement according to claim 1 or claim 2, wherein the second electrode is tubular and surrounds the first electrode.4. A gutter water level sensor arrangement according to any preceding claim wherein the hydrophobic material of the insulating block comprises a hydrophobic coating of the insulating block.5. A gutter water level sensor arrangement according to any preceding claim wherein the inlet flow path of the chamber is covered by a mesh or grille.6. A gutter water level sensor arrangement according to any preceding claim, wherein the main body is constructed out of a hydrophobic material.7. A gutter water level sensor arrangement according to any preceding claim, further comprising one or more resistors connected in series with the first and second electrodes.8. A gutter water level sensor arrangement according to any preceding claim, wherein the gutter water level sensor is fitted to a gutter.9. A gutter water level sensor arrangement according to any of claims 1 to 7, wherein the gutter water level sensor is fitted to a drain. (\J0 10. A monitoring system connected to a gutter water level sensor arrangement according to any preceding claim.11. A monitoring system according to claim 10, wherein the system is configured to determine the electrical resistance between the electrodes of the gutter water level sensor arrangement and to issue an alarm if the determined electrical resistance falls below a predetermined threshold electrical resistance.12. A monitoring system according to claim 11, further comprising an adjustment arrangement for adjusting the predetermined threshold electrical resistance.13. A monitoring system according to claim 11 or 12, wherein the predetermined threshold electrical resistance is between approximately 100k Ohms and lOOM Ohms.14. A monitoring system according to any one of claims 10 to 13, wherein the system is configured to issue an alarm over a network.15. A building including a gutter water level sensor arrangement according to any one of claims 1 to 9.16. A building according to claim 16 further comprising a monitoring system according to any one of claims 10 to 14.17. A gutter water level sensor arrangement substantially as herein before described with reference to the accompanying figures.18. A monitoring system substantially as herein before described with Q reference to the accompanying figures.19. A building substantially as herein before described with reference to the accompanying figures.