I need to terrace some stairs into a steep hill, but my well is at the bottom of the hill and my house is at the top. Therefore there has to be pipe and wires going up the hill somewhere. I don't know where and before we drive rebar to anchor the containing wall/stair we need to know where the pipe is.
If your water does not freeze up in the winter, they are presumably buried below frost line for your area - which is typically where they do get put by competent installers (and not terribly deep if there is no frost.) In my area that's 4-5 feet, typically. In most but not all cases it will probably be the shortest, most direct path from where it comes out of the house to the well. The only way to be sure is to carefully dig down and find it on either end, and then use those locations to try and find it nearer to where you might be damaging it if you blindly pounded things into the hillside.
Once you have found a few specific points, be sure to witness them in one or more of these methods:
- take very careful tape measure distance readings to fixed objects (the well-head if it sticks out of the ground, the corners of the house foundation, other objects likely to stay put for a long time) and write those measurements down on a map - you can then construct a triangle to find the pipe again by measuring from a fixed point as recorded on the map and making an arc, then doing the same from anther fixed point - where the two arcs cross, the point you measured the well-pipe at should be below (within some scope of error.)
- I'm fond of a more direct approach, where I construct an annual flowerbed or easily movable perennial plants flowerbed as a physical witness to the item below. You'd still want to save a map with the "important house paperwork" and hope it doesn't go missing, but there's no doubt where to dig unless someone obliterates the flowerbed in question. If you remember not to move it, some sort of lawn decoration could serve the same purpose, but a flowerbed is more lasting.
- A section of inexpensive PVC electrical conduit just shorter than the depth to the buried item and marked (both what, and from 0 at the bottom to how long it is at the top as a measuring device) with permanent marker can also be buried in the hole as a guide to future digging. The idea being that you can find it quickly as it's just barely buried, and then follow it down and know how close you are to the buried item.
One safety note: if you at ask think there is a chance you can hit the line, turn off power to your pump while you are working. Better safe than sorry.
First of all, the water lines are almost always buried below the frost line. There are exceptional cases where bedrock prevents this, and if there is no other path the lines may be shallower with insulation and possibly heat line, but this is pretty rare.
The power lines are almost always buried right beside the water lines, often both inside a length of "big o" (corrugated black 4" HDPE) .
Locating via guess
You can take an educated guess by looking at where the lines enter the house. Generally it will be the most direct route that doesn't have any sharp turns.
Locating using a wire tracer
You can rent a wire tracer that will fairly accurately trace the path of underground wires. There are also companies that will do this for you. This will only work if there are wires (submersible pump), or if you cut the water line and run a fish line down it that can be traced.
Obviously the most expensive, but may also be the only way without digging it up. It just really depends on the distance involved and how close the line likely is to the spot you are digging or installing rebar.
When in doubt, Call Before You Dig (your gas, power, water and telco companies). Your municipality may have a system in place to make this easier, E.g, 811. They will come out and mark where their utilities are so you don't hit them.
Concrete footings must begin below the frost line. Hopefully you don't find it when digging out for the footings. Rebar gives concrete strength, they're not 'piles' to be driven far off into the ground. If you do find it, make sure X marks the spot as Ecnerwal suggests. My 'archives' have saved me countless headaches.
You can buy (or maybe rent) a wire tracer like this:
The power wire to the well would have to be disconnected from power and the left box connected to the loose wire. Then walk around with the sensor near the ground and see where the wire goes. Its range is reduced by the soil so if the wire is very deep (> 18 inches?), it may not work so well.