We are having issues with water usage at our house we recently moved into. I suspect either a water leak, bad water meter or theft of water by a neighbor.
My house that we recently bought is about 300' from the water meter. After we closed on the house, we didn't move into it for approximately a month. Our first water bill showed we used 3200 gallons of water, when we were only there about 3 days that first month and we probably only used maybe 100 gallons. We were still living in our prior house until the movers moved us a month later.

I've checked the toilets, etc. and do not see any posiible leaks from the inside plumbing. I don't see any water leaks above ground for the 300' of water line to the water meter.

The only possible issues in my mind are either a neighbor tapped into my water line or a bad meter (if that is possible). I plan as my next step is to turn the water off at the valve just inside the house, take a water meter measurement, keep the water off for a day or 2 and see if the meter advances any (1 number increase in the meter is 100 gallons). If I see water being used that means either a leak between the water meter and house, bad meter or theft of water. Next step would be to cut the water off at the meter at about 6 am on a work day (Monday through Friday) and observe my neighbors' houses in near proximity to my water meter when they would typically be getting ready for work. I don't think they would be stealing my water, but just eliminating possibilities. If I still can't figure it out I plan on buying and attaching one of those real time water meter attachments that you attach to your water meter and it sends real time gallons being used over a radio transmitter to the receiver inside your house. I would fill up a 50 gallon container 4 times and it should measure 200 gallons. I would check that against the water meter measurement to make sure it is inline and moved exactly 2 numbers. Plus we would not use any water in the morning and see if it registers any water being used during the morning getting ready for work time for my neighbors. If I saw we were not using water but then real time I could see maybe 60 gallons used and then it stopped abruptly, then I would know a neighbor is tapped into my water.

So my questions are, does this sound like a reasonable plan to investigate my water problem. Plus, is it possible that the water is running back and forth through my water meter so for example it registers 2 gallons for every 1 gallon we use? If so could I fix this by hiring a plumber to install a check valve either just inside the house in the water line or just after the water meter very near the water meter? Would installing a check valve cause any issues. We have a tankless water heater so I assume an expansion tank would not be needed if we installed a check valve to stop water from going from our house back into the city side of the meter where we would pay for it again.

Any advice is appreciated. Thanks.

This post was edited on 12/21/22 at 8:13 pm