DIY Guest House Renovation: Water & Electric

We were thankful and lucky that the guest house already had a fully-functioning bathroom, complete with tub/shower, toilet and sink. And while the garage/guest house had working plumbing, electric and water, we weren’t too confident of the quality and workmanship of the electric and water feed. The sewer/plumbing turned out to be installed correctly so that was one thing we didn’t need to worry about. The electric and incoming water was another story.

Frankly, I couldn’t find and trace the exact water line that went into the guest house but I knew it was part of a rapidly deteriorating, 60+ year-old galvanized pipe system that fed old sprinklers and a few rusty spigots in our backyard. The pipes were paper-thin, well beyond the typical 40 or so years, and I didn’t want guests to drink rusty water. Since I was going to abandon the system anyway, I decided to run a new water line from our main line.

The original electric was just as sketchy. Whoever ran it previously just spliced it into our main electrical panel with a 30amp breaker and ran an electric line (not even protected in pipe) under our driveway and then spliced it into the original cloth-wrapped wiring in the garage.

Before digging, I called my local 811 “Call Before You Dig” service. They came out FOR FREE and marked ALL my utility services.  I’m glad I did, because the incoming electric AND gas lines to our home crossed right over where I was going to be digging. Nothing like putting a pickaxe into a 240 volt electric line to end your existence, eh? So with the utilities marked, the shovel and pickaxe came out, and I got to digging. Our main water line and electric panel are right next to each other, so I planned to have the new electric and water lines share the same trench for a short distance.

diy trench digging

Nothing like digging through caliche! The main electric panel is seen on the left. The two gas lines are circled in red.

You’ll see our main electric panel on the left and the trench. You can even see the unprotected original electric line in the trench as well as the incoming gas line, as well as a gas line that was fed to the guest house (highlighted in red).  Just past the gas line going to the guest house, I split my trench. The right split was going to be the electric line, while the water followed the gas line under the side fence and into the backyard.

utility pipes crisscrossing

Yeah, this wasn’t fun to dig through.

Boy, was THIS a pain to dig! As the lines went under the side fence, I found an old, original slab of concrete that was hidden under the topsoil. Not only did I have to dig UNDER the slab of concrete, but the gas line, the new water line, the OLD water line, AND the outgoing sewer line all converged at this exact point. I spent hours with a garden spade trying to get enough room at a legal depth so we could run the new water line. You can see here how badly corroded the old galvanized sprinkler system is.

hidden concrete patio

Surprise! I ended up having to remove quite a few more bricks and dig around the original concrete patio.

After making the turn, I thought it would be a straight run alongside the guest house to where I was going to feed the water into the wall. But, nope. I carefully removed the brick patio so I could set them back into place when done. But hidden underneath the bricks and about a half-inch of soil, was a huge, thick slab of concrete. The original guest house door patio!  There was no way I was going under or through it, so I had to remove quite a few more bricks and dig around the perimeter of the patio. Thankfully it wasn’t that big.

guest house before photo

Guest house as we began to renovate it to it’s current awesomeness.

Here is a great “before” photo of the guest house, with the new trench dug. You can see the gas line coming out of the ground to the left of the window. We don’t need the gas line now but decided to cap it off and keep it in case we do in the future. You can also see an old, badly rusted horizontal gas line that ran into the guest house, where I believe it must have fed some sort of heater.

The stain on the wall you see used to be a completely exposed (and illegally vented) gas water heater! The two pipes you see poking out of the wall above the stain were the water heater pipes. The window was missing a pane of glass, the screen door was broken, and the door’s sliding window was not functional. You can also see the ugly, dilapidated fence, which we have since replaced.

We easily replaced the broken window glass with a pane cut at our local Ace Hardware, and some window putty. Replacement doors can be expensive, and there was nothing wrong with the door itself. So we found out what brand it was, and ordered just the replacement sliding window portion for a fraction of the cost through Home Depot. The cheap, broken screen door went bye-bye, and we plan on adding a security type screen door in the near future.

dangerous house wiring

Examples of some of the really bad and dangerous wiring we found in the garage and guest house.

Oh, the electric line! I decided to remove the old garage-side drywall so we could install the new electric and some insulation. Even to my unprofessionally-trained eye, I could tell the wiring was dangerous. You can see how the lines were badly spliced into the original cloth-wire! This is one area where we hired professionals to come out and install everything up to code, fully legal and safe. They ran a new line to a brand new sub-panel, and re-wired the guest house for us, including dedicated lines for the kitchen, under-counter water heater, and air-conditioning unit. They told me later that they found a few spots where the lines had burned and nearly caught the garage/guest house on fire! I think all said and done, the electric cost us about $1500, which I was MORE than happy to pay to have safe, up-to-code electric.  They even left me half the panel so I could run electric for the garage when I can get to it (hint: future blog!)

Thanks for reading!  As always, I’m happy to answer questions, and keep an eye out for the next chapter: Drywall!


  • This guest house renovation looks like a huge project. It’s amazing that you were able to do most of the project yourself without hiring a residential electrician until the very end. I’m glad that you reminded me to call 811 before digging to mark my utility services. I’ve been wanting to run an electrical line out to my shed but completely forgot that calling before I dig is very important. I’ll definitely be sure to take your advice and call before I dig.

    • Patricia Winter-Hunt

      It was a bigger project than we realized (aren’t they all?). Good luck with your project – what will you be doing?

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