I am moving my washing machine and need to run a line underground along the back of the house, My question is how deep does this pipe need to be. It doesn't get that cold here in virginia(southern virginia, Virginia beach)

Hey Massmustang... I posted... then reread your post. Now I unposted.. and want to know... is this outside underground or inside undergound..? And if outside... why..? Your turn.

It is outside under ground because the laudry room is about thirty feet from the main line, and the house is on a slab. So I dug under the slab by the laudry room 90'd and ran straight acoss 90'd to under the kitchen where I can tie into the main line. I actully have a pump there to pump it up into the main since the main is tight up to the slab

Hmmm.. well... I am confused... contact me via private message please. Do you have a trap and vent to this washing machine? What happens as washing machine pumps into drain.. AFter drains... does it drain by gravity to outside and then inside or do you need pump to do this.. Your turn?

I live in northern Virginia, the frost line here is either 16 or 18 inches. Yours won't be quite that deep. Call the city building or plumbing office.