Mains or waste water leaks account for about 5 – 10% of water damage in surveyed properties, yet are rarely tested on contractor damp surveys.
Tips for identifying leaks
- Test the mains water for leaks – see https://youtu.be/7EphH-iZxes.
- Make sure there is no water being used, including from toilet cisterns.
- Either look for movement an analogue central spinning meter if available, or leave the system off for a day and look for meter reading changes, or use a mains water pressure gauge:
- Shut the stopcock off.
- Test that the cold water tap has stopped running water. If it is still running, then either the stopcock is not turned off fully, or the tap is connected to a cold water tank (tanks should not feed drinking water taps). In such case, consider plugging the cold water tank feed.
- Put the mains water back under pressure.
- Test the water from an external pipe or washing machine pipe using a mains water pressure gauge for about 20 minutes (note external taps often leak when on, leaking taps should not be used).
- Return the stopcock to open and check water is running correctly.
- There should be no movement in the dial. You can work out the speed of flow, by testing replicating the drop in pressure and measuring water from a tap.
- If there is water loss, then double check “innocent” flow from taps, showers, tanks and cisterns and replicate test.
- Once a leak is established either test every section and joint for water, profile with a damp meter or infra-red camera (for heat loss), look for rust or other tell tale signs, or you may need a specialist leak detection service such as from leakbusters.net (no affiliation).
- Test for a wastewater leak. Use a florescent (ultra violet) or blue dye (beware that this can leave a lasting stain) in waste pipe. This test is not always successful as a long term leak may not allow sufficient dye to pass through into a floor or wall.
- Measure the walls dampness with a Protimeter data-logger or by logging with a damp meter weekly, seeing if readings go up or down, depending on usage.
- Use a nitrate or chorine test to establish if the moisture is from the local waterboard’s source, that is mains or a waste water leak (water from rain or condensation is free of nitrates and chorine).