Our tub is filling with sewer water but we aren't using any water. We have had clogged main line in the past but as long as we don't use water the tub won't fill. This time our tub is filling even though I shut off our water main. It rained a little today , could that be a cause.

Hi Dennisscott1

My guess would be that your main drain is clogged AND your toilet FLAPPER is letting water leak by so that even when you shut off the water main the water keeps draining into your drain and showing up in the tub... ;)

Here, to start, I would do a DYE test where you drip about 20 drops of a dark food coloring into the toilet TANK only and see if the color shows up in the toilet BOWL say 1/2 to 1 hour later. If color shows up you have found the source of the running water (even when the main water is shutoff as the toilet tank has a good reserve of water).

Try the dye test and then plan on getting the drain line snaked (or the septic pumped? ).

Mark

Rain should not do this even if you are on a failed septic and its pouring cats and dogs. Agreed main is clogged but many things trickle water into your sewer line including your furnace condensate line, house humidifier, ice maker and of course the toilet like Mark is suggesting