Our house is at the bottom of a slope, and all rain water and irrigation runoff gets collected through a underground pipe which has an opening at street, a few yards away from storm drain.

We recently found a small amount of water constantly yet slowly coming off the pipe and thus get collected on the street. There is water even when sprinkler is off for whole week and no rain. Where can this water come from? We do have a damaged sprinkler for the lawn (riser does not come up, nearby sprinkler heads lose water pressure ). there is no leak according to water leak gauge for the whole house. Can anyone please help diagnose the source for this water?

2 Answers 2


These sort of leaks can be notoriously hard to track, some of the possible causes can be

  • A spring in the area that may have been diverted due to earthworks in the area
  • Neighbouring property having a water leak that is running into a ground water drain on your property
  • Having a roof mounted solar hot water system that is leaking
  • A underground water leak

I noticed you said you have checked the meter for a whole house leak. That is good and I would recommend you do that by turning off all taps toilet cistern taps and washing machine taps etc, then go to your meter write down the reading and leave the test over an hour if possible as very small leaks can be difficult to detect on a whole house meter.


The underground pipe can pick up groundwater through very small seams or holes, and water can also run under, between the bottom of the pipe and the ground. I have both cases going on at my house. The amount that drips is about 1 drop each second from the pipe even if no rain lately, and I can't tell how much goes under but I think more goes along under the pipe, which has gravel under it, than goes inside the pipe. Until I got that pipe, my basement had water trouble and now it is completely fixed, which is really hard to believe but true.

Also I did an experiment: one drop per second filled 1/8 cup in 100 drops, call it a minute and a half. That is 12 minutes for a cup, 5 cups per hour, a gallon every 3 hours, 8 gallons per day. It builds up!

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