Im having a slow leak into my septic tank. I had it pumped today and see the water dripping from the inlet tube. Its a slow but constant drip. Heres what Ive done so far to trouble shoot. 1. Checked all toilets: None running. I turned off all water valves to tanks and even sucked water out of tanks to make sure there was none seeping under flapper valves. 2. checked all faucets- no leaks. 3. Turned off main water valve at hot water tank and checked meter at the street. meter was not running so Im guessing the leak if from inside the house. 4. The only thing I can think of is that its coming from the hot water heater since its under pressure. Could this cause a slow leak even if water is turned off to toilets? I realize the hot water does not run to the toilets but would the pressure from the tank cause a leak into the septic tank? Could the small expansion tank that is attached to the top of water heater cause the leak issue? 5. I opened the relief valve on the water heater to see if this would stop the drip-no luck. Any suggestions on what to check next would be a HUGE help!