If a landline - phone, electricity, gas, or water, crosses your property you will most probably not be able to build a house over the line. Homes require stable and deep foundations and the authorities will not allow you to build.
But what about a shed? Can you build a shed over utility lines? It depends.
The first thing I would do is to see if there is really no way to build the shed aside from the utility lines. It's better to choose less convenient location rather than having to deal with the lines. If not, here's what to do:
Check Your Zoning Laws and Authorities
I wouldn't advice you to build without first asking if it is allowed. You can end up being fined and having your shed destroyed. Ask at the local zoning department and make it clear that you want to build a shed and not a massive building. If they don't forbid, you can take the risk. But the best solution would be to get a permit.
In case you have not received clear parameters what you are allowed to build, you should build your shed with a deck pier foundation. This ensures minimum drilling in the ground and not too deep holes. Typically the electricity lines are burried at 18" or so. Water would be deeper. Cable TV or internet might be on different depth however. You have to drill carefully and slow, on hand. If you know where exactly the lines are, make sure there is no hole exactly over the line. It's best to call the local utility locator service to come and spray the lines for you.
Then build the foundation frame and you can build on top without further issues.
Here are few articles discussing similar problems. Have a look for more information:
- Power line/Building code/NESC- boat shed
- Building a Patio Over Buried Utility Lines
- Can I build over the main gas line coming into my house?
- Building over electric/telephone/cable utilities
Here are few extra tips:
- If possible, move the utility lines. It might be a hassle, but will let you build your shed without any hassles.
- If you decide to keep the lines, think about the slim chance that repair will be needed right under your shed. You must have a plan to avoid destroying the shed.
Once all is considered, go ahead and build it!