This might fit better in the DIY group but here goes.

How do I know when it’s time to have the septic system pumped out?

We had a new one installed 3 years ago. It was an upgrade in size. I’m not sure the capacity. It was negotiated to be done as part of our purchase contract, and the old owners didn’t give us a copy of their contract with the installer. Just the inspector’s report that plans were adequate for the number of bathrooms we have.

There are only 2 of us. We don’t put that much water into the system. But we’ve been having a LOT of rain. Over 5" in the last week and a half, and over 9" since Jul 1. Our elevation is between 1 and 4 ft (not a typo), so the water table is very close to the surface here.

I’m getting periods of methane smell in the house off & on for about a month now. I’ve run water to make sure all the traps aren’t empty. It’s possible it could be coming from the vent stack for the washing machine, but it’s not all the time.

So with not a lot of use put into the system, is 3 years too early to have it pumped out? How can we tell?