Hooking up to house sepitc

To explain why people say don't dump it all at once... Remember, a septic tank operates 'full'. Every time something goes in, the equivalent amount goes out. Normally if this is a toilet flush or shower water, that amount of liquid simply flows out of the tank and into the drain field. If you dump 40 gallons or more at once, the drain field may not be able to accept that amount in a short time and the whole system could back up to your dump receptacle or make the drainfield area very soggy and stinky. Neither a washing machine nor a bathtub, while dumping the same volume, will do so in such a fast manner. Not dumping all at once can also cause the problem of most of the liquid leaving the black tank first leaving a lot of solids behind.