Once it got hot outside, my toilet bowl fell to a lower water level than during other seasons. Sometimes it takes more than one flush to clear the bowl. I made some minor adjustments to get it back to a reasonable height only to find it drop down again. Am on a septic and this toilet (1 of 2) is nearest the main discharge line. Any ideas what is going on and why this only happening in the summer?

Once it got hot outside, my toilet bowl fell to a lower water level than during other seasons. Sometimes it takes more than one flush to clear the bowl. I made some minor adjustments to get it back to a reasonable height only to find it drop down again. Am on a septic and this toilet (1 of 2) is nearest the main discharge line. Any ideas what is going on and why this only happening in the summer?

Toilet bowls lose water for a number of reasons, Evaporation from the AC. a bubble in the bowl casting that slipped by inspection and got installed out in the home, or suction that pulls the water out of the bowl when water discharges past it without a proper vent. It's hard to nail down a problem such as this without being on the site. You will have to narrow the choices down by elimination. Tonight before you go to bed fill the bowl and make a pencil mark at the water line. DO NOT discharge anything past this fixture until you've checked the level in the morning. If the level hasn't gone down then start flushing and discharging water upstream from the toilet. Leave it alone and see if discharging water past it will lower the water level. Then get back to me with the results. Cheers, Tom