I’m just posting to thank you for using the bolded word properly. Its a bit of a peeve of mine.
When I bought my last home, my water bill was very high, but it was a new home and I didn’t know that it was higher than normal. The next month it was even higher, but it was summer and I was watering plants. A couple of months after that, I was standing outside smoking something and heard water running.
It turned out to be the pipe from the meter to my home. My home that was on the side of a hill and all the water was running under it and messing up the foundation and supports.
I had the exact same symptoms as the OP, and it turned out to be a water main leak. You won’t notice any leaks in your house. I didn’t notice any soft or wet ground around the yard (and I live in the desert.) Just a huge bill.
The way I found that was to shut the water off to my house, and then check the meter. There’s a flow indicator on the meter. It’s a little gear looking thing on the display, that spins when water is running through the meter, and stops when no water is flowing through the meter. The gear was spinning, even though no water was going anywhere in my house.
There is a shutoff valve next to the meter, on the city-side of the meter. I had to use that valve to stop the water flowing to my meter. Then I had to pay a plumber to replace my water main line (the “main” is the line that goes from the meter to your house). This required digging up the old pipe, which ran under the sidewalk. Total water bill, 850 bucks. Total plumbing bill, 2,000 bucks.
I too was served up an enormous water bill a few months back. Had a plumber come out and check for leaks and he found nothing (except a few floppy valves in the toilet tanks which he fixed, but didn’t solve the problem). So I called the city and they suggested I turn off the main water supply, then go look at the meter. It was whirling around in spite of the water being shut off.
Took a while to identify the location of the problem and they had to send a camera down my pipes to find the leak. Turns out the leak was in the main line coming into the house (tree roots had grown thru the line, causing it to rupture). It was thousands of dollars to diagnose the problem and replace the main line, but the city was surprisingly helpful. They gave me a credit on my next bill—can’t remember how exactly it was calculated since they don’t monitor daily usage. I think they took the old bills and averaged our usage–then applied some huge credit to our bill.
In any case, I hope you solve the problem soon, but an underground leak is what might be happening.
Finally got ahold of someone knowledgeable at the utility. Turns out the stupid meter reader (and not incidentally, stupid me) was reading the meter wrong. The last 2 digits should not be read, since the bill is in 100’s of gallons. So when the numbers on the meter read “420”, the billing amount should have been “4”
My theory is that when the meter dials flipped over from 99999 to 00000, this confused the meter reader. He was unaware that he should not be reading the last 2 digits.
Also, the math doesn’t seem right. If you were charged for 420 “units of measure” instead of 4 “units of measure”, the difference in your billing would be quite a bit more than 6 times your average. Seems like it would be 100 times larger.
(I use the term “units of measure” because most meters that I’m familiar with measure water by the cubic foot and their dials are calibrated to read and display thousands of CF used. Obviously, your meter may be different.)
When I checked then “with no water running”? Apparently when I said “don’t use any water” and went out and checked, this seemed to mean (to a 13 year old) “go ahead and have a shower, just don’t drink any”
Another confusing factor is that the meter went from 999999 to 000000 sometime during the billing cycle. So for most of the billing cycle the charge would be normal. The mistaken increase would only have been for the 0 - 420 part. If that makes any sense.
