I shut off main water valve, but water meter shows water usage.

[Steven Tu]

Before I was out of town for 1+ month in January-March (snow months), I shut off the main valve. However, the subsequent city water bill still showed a non-trivial water usage (6 CCF). I checked and didn't find any in-house water leakage. Is the water in the sun pump included in the water bill, since my sun pump is operating frequently?

Thanks.

Steven

[Bob H.]

You didn't say this was a single-family home. Consider this scenario, which happened on the first property I bought, many years ago. My townhome was an end unit in a newly built row of four. Another single guy lived in the other end unit.

When I went on vacation, I had an unexpected water bill. As it turned out, the meters had been marked wrong after construction, and the two of us paid for each other's water for months -- maybe a year. Only the vacation made our bills different enough for the error to be discovered.

If the meter clearly was yours, consider a leak between the meter and your main valve. To check for this, turn off the main valve again in the evening. Then read the meter carefully. In the morning, read the meter again before turning on the valve. If you see any usage, you must have a leak.

Also, the meter itself probably has a valve, which may not be the one you turned off. You could experiment with the result of turning off that meter valve.

Your sump pump should be expelling ground water that has migrated to the basement or crawl space. Barring a leak in a pipe, that water should not be coming from the water utility, so it should not affect your bill.