I'm going to be installing about 60 feet of PVC underground. I've never had to do this before so any advice or suggestions would be appreciated. How do you go about sloping your ditch correctly? I'm running 4 inch PVC and I was going to slope the pipe at 1/8 inch per foot. How do you go about digging and checking your grade? What happens if I dig a little bit too much out? can I just back fill it with dirt? what do you guys use to check your slope whenever you dig a ditch?

A transit can be used to check the grade, or you could tape a 1/2" block of wood on a 4' level , if it shows level then you're at 1/8" per foot grade. If you must backfill make sure it's tamped in.

As long as you have some slope in the line you will be ok, even if it is more than 1/8". You just don't want to have a section that slopes downward and then upward and then downward, that will create places for water to accumulate. Unless you are filling the trench with a filler (like sand or pea gravel) try not to dig any deeper that needed because if you have to put the dirt back in it won't be as solid of a support unless you go to the extra work of tamping it. Take your time and check the slope regularly.

If there is a tool rent-a-center near you they probably have a trenching machine. They are fairly easy to operate and can save you a lot of time and work, especially if you are digging thru roots and rocks.



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I use a laser to check ditch gradients or if you have a good backhoe operator you tell them how deep it needs to be at the building and how deep you want it at the end of the line a good operator will hit it 99% of the time.

PlumbCat TM 2003


Plumbermandan

fine sand in the bottom of the trench makes grading very easy. no sharp stones...