The basement in our house has a full bath in it. The basement floor is below the level of the septic tank, so there is a lift pump that pumps the sewage up to the drain to flow into the septic. My first experience with one of these. Anyway, I suspect there is some ground water leaking into the sump for this pump since during a hard rain it will run when there is no use at all in the downstairs bath. then after the rainwater has drained off, it normally doesn't run until I take a shower down there. Question: is this necessarily something I should have looked at? I don't like the idea of pumping a lot of rainwater into the septic, but it doesn't seem to cause a problem....this septic has sand filters, so the water is filtered and drains to the local waterway (I guess, it's all approved by the sanitation engineer).