The Supply line: So your supply line burst… again shut off the water. Dry things up and disconnect the supply line if you can. There are some supply lines that directly connected to the shut off valve. These were very popular in the 1960’s to 1990’s. Then someone came up with braided supply lines. There are pros and cons to both as with everything, but I like the braided supply lines, so whenever I come across them I end up changing them out because it just becomes much easier to work with in the future. So If you’re going to change the supply line I also feel it is a good idea to up date your shut off valve from a multi turn gate valve to a quarter turn ball valve. To do this you will need to shut off the water to the house unless you have the ability to isolate the flow of water to your bathroom or toilet. (if you have PEX piping in your house this is a real possibility, you just need to know where your manifold is, usually in the garage). Once you have the water to the house or isolated off, you can disconnect the shut off valve. There are two types of connections (most commonly used anyway), one that uses a compression fitting and the other is were your copper pipe is threaded. If you have PEX piping, you may still have a copper connection for the shut off valve so check before you continue on.
Assuming that you have a copper connection, you will want to look very closely at the back part of the shut off valve. If it is one solid piece, your pipe is threaded, use caution when trying to turn the shut off valve, this is where pipe can get broken if you’re not patient. If you see what looks like a nut and some visible threads on the valve, you have a compression fitting. Use caution when trying to loosen these connections, and use two wrenches as you can bend or break the pipe if you use too much force. If you see water corrosion on the valve or around the threads it is a good idea to get a metal pick or something similar to scrape away anything that could bind up the nut. Lightly tapping on the valve can also help to the loosen or dislodge the corrosion as well. Have that small bucket ready because there will be some water still in the pipe once you have gotten the valve off.
TIP: After you shut off the water to the house, run the bathtub or sink furthest from the toilet (or any water fixture you are working on), this allows air into the pipes and moves the water away from the area you’re working on. This also can give you a heads up if there are any issues with your main shut off.
If you have a threaded pipe, you’ll need to get a threaded pipe shut off from the hardware store or home center. You’ll want to take the valve you took off to the store to match the size pipe you have. Most common toilet fittings are 1/2” (1/2 inch) pipes. I also recommend getting the “toilet” connection supply that has the plastic compression fitting for the toilet side. The reason is most of the toilet inlets are plastic, and if you use a metal connection, you have the potential for stripping the threads and that can lead to leaks.
If you have a compression fitting, you have a little more work to do, but not much. Once you get the valve off you’ll notice the compression nut and small brass ring are still on the pipe. And while it is tempting to leave them there and just use them with the new valve, I don’t recommend it. So you will need to remove those from the pipe. The fastest way to do this is to cut the pipe behind them if you have enough room between the nut and the wall. If you don’t, then you will need to cut both the nut and the brass ring. Using a small hack saw can the job done, but if you have a Dremmel with a cut off wheel, you’ll get it done faster. Once you have removed them you’re ready to replace the valve.
When replacing a compression fitting, having a clean, smooth copper surface is best. Using some sandpaper 100 or 120 grit will clean the surface of the copper pipe and you can slide on the new compression nut and the brass ring in that order. Slide the nut to the wall, and then once the ring is on the pipe, you can press the valve into place. Push the valve back as far as you can. Then proceed to tighten the compression nut. DO NOT (Sorry, not yelling, just emphasizing) use tape or putty or anything around the threads of the compression fitting. It is not needed and can make it very difficult to remove the fitting later. You also do not want to over tighten the fitting. Hand tighten the nut and then with two wrenches again, tighten the nut a 1/4 turn more. Make sure the valve is in the closed position and turn back on the water. Check for any leaking. If there are leaks, try tightening the compression nut a little more. IF after tightening a total of an additional 1/2 to 3/4 turns and you still have leaking, go turn off the water and try to reseat the brass ring. You may need to clean the pipe a little more. Once you have the valve on and it is not leaking in the off position, you are ready to attache the supply line. Remove the compression nut and brass ring in the supply connection side of the valve. Attach the supply line side that has the corresponding compression fitting. Again, do not use tape or putty. Now that the supply line is connected to the valve, you can clear the line by putting the supply into a 5 gallon bucket and turning on the valve. Check for leaks. If everything is dry except for your bucket, turn off the valve and connect to the toilet. Again turn on the valve and check for leaks. If everything is dry, congratulations!