I notice that I can hear water trickling into my septic tank for a few days after a hard rain. It is a sand mound system, and it comes from the tank with the pump. I'm still waiting for the septic people to come out and tell me why...they want it to dry up a bit first. Now we do have a lot of water here, when it rains pretty good springs come up out of the ground all over the place. I havent heard this for the last 2 years, but my neighbors just tore down their mobile and put up a doublewide with a foundation. And they have this black flexible pipe that water pours out of when it rains and flows into the base of my sand mound. Enough that there is a swamp there for a few days after it rains, but in all honesty that isn't the only swamp here after it rains. But it didn't used to pool there before they ran their run off there. So any ideas what might cause this? And is it possible it is their fault? And how do I handle it if it is without getting myself in trouble and having the epa or township decide I need a new $15k septic?