Can you run your water supply from existing house and your electrical service in the same trench? If yes - assume you would do this by stacking it in same trench with water supply on bottom? Part of me says it seems crazy and then part of me says they are both in conduit and does it really matter. Williamson county if that matters. I did a lazy search on wilco web site but could not find much.

We did this years ago w no problems, and will again soon. In country w no inspections etc. (Check local listings I guess)..

I plan to trench 3-4' for water line, add 6" or so dirt before conduit, and add a strip of caution tape a foot or so under the surface. Like you said they're both in conduit so extremely minimal chance for issues if glued up right.

Will watch for expert replies.

ETA: small 3/4" conduit (light service) and 1" water, 70 or so feet out to a garden.

There's not a code requirement for separation of electrical/water - nor could I find a Williamson County requirement that they be separate. But it's very often a city municipal requirement, and almost always a utility requirement. Reason being, if you are digging one up, you might damage the other if you don't know that it's there. Pretty typical for this to be something like 12" between the two. I'm not sure if water supply and sewage can be in the same trench per code, but they're almost always separated.

As long as you're using cable rated for underground or conduit, it's not a water exposure issue, so the water above or below electrical doesn't matter much. I'd be skeptical about putting them in the same trench myself if I already had a trenching machine on hand. But if I was going to put them in the same trench, I'd put them 12" apart with some utility marking tape in between them(example), and another layer of marking tape above the top supply.

I know from one source that water supply and sewer can not go in same trench. Talking to excavating guy working on the house next to me was not fur sure but he knows he has seen sewer and electric supply in same trench. I just don't have affirmative on electrical and water supply. Leaning on its probably fine. I like idea of marking with utility caution tape.

To clarify above - utility requirement meaning utility companies - ie Centerpoint, Atmos, etc. Not a water or electrical requirement. Those companies don't want you in the same trench as their installation.

95richmondaggie95 said:

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Can you run your water supply from existing house and your electrical service in the same trench? If yes - assume you would do this by stacking it in same trench with water supply on bottom? Part of me says it seems crazy and then part of me says they are both in conduit and does it really matter. Williamson county if that matters. I did a lazy search on wilco web site but could not find much.

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Even though your electrical is in conduit, it's still considered a "wet location." So your wire should be wet rated. No problem putting them in the same trench other than you'll have to deal with one of them if you need to excavate for repair.

For what it's worth, experience with a 1979 water line 1.25" x 130yds
has only had leaks twice at/near my side of the meter box. Aggieland highly expansive clay soils.

Ergo, my situation might make me think about keeping the electrical from sharing a trench until 10-20yds away from meter area. Personally, I would not sleep well if two of anything shared a trench due to Murphy ('s Law) visiting often enough as it is. Of course if I was a tax funded City with time/equipment fixing low bidder stuff - a horse of a different color.

That said, metal storage sheds get 100v15a power via 30yds of slightly buried yellow extension cord 12/3 for over 20 years, even run under parking areas.

Thanks for all the comments-my main reason for wanting use the same trench is the rocky nature of the soil and trenching costs can become sporty in this goshforsaken ground!. I am not sure what wire I am taking over there but my electrician said I will need 2" conduit. He put in larger service at the house knowing we would have a sub panel on the metal building One day. I will want 220 for compressor and minisplit and enough juice to add heavier tools one day.