Sump plumbed to water drain

[untamed]

My system is directly connected to the house drain in two places.

1) The Water Change Sump has a drain valve. I collect 50 gallons in this sump...open the drain valve...close the drain valve...and refill to 50 gallons. That's a water change.

2) The main sump has an overflow that runs directly to drain. This overflow has never been used, and I really think it is impossible for this sump to ever fill that much. In fact, it is probably a liability now more than a safety net because it exposes the system to a possible backflow from the household drain up and into the sump. (that would be bad) I meant to put a check valve on this overflow, but I never got around to it.

Sorry...no photos available.