Plumbing isn’t easy. If it was, everyone would be able to fix up their entire house without an issue. Unfortunately, there is a lot more to plumbing than meets the eye. Even the simplest of fixes can potentially lead to larger problems, like leaks that go unnoticed for days or months, causing years worth of damages. Instead of learning the hard way, read up on this list of common DIY plumbing mistakes.


That way, you can avoid additional mayhem and get the job done quickly and efficiently.


1.You Didn’t Slope Your Pipe Correctly

In order for water to drain properly, you need to slope the pipe. Here is a hypothetical scenario: Let’s say you do not slope the pipe and do not install a vent. When you flush the toilet, there will be negative pressure throughout the plumbing system and air will be siphoned from an adjacent P-trap. This will then push sewer fumes up through the pipes and into your home, where such gases can make you ill.


You will know the pipe is placed well when it does two things:


  1. Waste flows without any obstruction or backup in the right direction
  2. There is no siphoning through the P-trap


In short, look up tutorials on how to slop the piping correctly before doing it yourself.


2.You Reused Flexible Hoses

Do you know the weakest link in your home’s plumbing system? That would be the flexible speedways—or hoses—that are made of rubber and encased in a jacket of stainless steel. Flexible hoses last around 5 years and need to be replaced soon after. Otherwise, you could be dealing with leaks and other issues.  Don’t reuse them. Ever.


3.You Used a Lead Solder on a Drinking Water System

Before the 19th century, humankind had yet to recognize that lead was toxic. It was used in all kinds of applications, including soldering copper plumbing pipes together. Although lead is banned these days, you may still find it in homes that were constructed before the 1980s.


You can still purchase lead solder. Just don’t use it on the pipes for potable water. Instead, use a 95 percent tin, 5 percent antimony solder.


4.You Didn’t Deburr Your Pipes

Burrs, or inward facing ridges, are formed inside the pipe when it’s been cut. Burrs reduce the diameter of the pipe, creating turbulence when water rushes through. While it is not an immediate issue, turbulence may cause damaging leaks.


Always deburr cut pipes by smoothing the insides with either a reaming tool or a utility knife. Pipe cutters also have tools for deburring.


5.You Didn’t Install Water Hammer Arrestors

First off, what is a water hammer arrestor? It is a fixture that absorbs the shock of water flow that has been suddenly shut off. A “water hammer” is the resulting effect of a fast shutoff valve from a dishwasher or washing machine, where water pulses through the water line.


You may already see the problem that comes with not installing them through the description alone. Before water hammer arrestors were invented, there was a common T-shaped pipe that was filled with air to cushion against hammering. However, those T-shaped sections could fill with water and stop functioning properly.


If you want to stop water hammering, it’s highly recommended to get some arrestors installed.


6.You Didn’t Hang the Pipes Properly

If you do not hang plumbing pipes correctly, it could become a problem over time. This is because water and pressure will mount at the joints, forcing a leak, and that will lead to water damage.


To prevent such leaks from happening, it is recommended that you attach hangers every 6 inches or so, so the pipe is properly stabilized and balanced.


7.You Didn’t Properly Clean the Copper Pipes and Fittings

Always clean the pipes and fittings before you solder, especially if it’s copper. You may not see it, but store pipes will have oxidized and need to be cleaned before you solder it.


To clean the pipe, use an abrasive material to scrub it until it’s shiny.


8.You Forgot to Isolate the Exterior Hydrants in Winter

Frozen pipes are ticking bombs waiting to go off. Prep your exterior for winter by isolating the valve from inside the house then draining off any water from the outside. Or, you can install a non-freezing spigot and never need to worry about it.


9.You Put on Pipe Dope Before the Teflon Tape

There is a lot of debating surrounding the proper method of Teflon tape and pipe dope and the order in which you apply them. Some people say you should stick on pipe dope first then wrap with Teflon tape while others go the other way.


Here’s the issue with doping then taping: If you wind the tape too tightly over the dope, it will get pushed back instead of sticking to the threads, which could cause leaks.


That means the proper way is to install the Teflon tape before the dope. Plus, you get a cleaner looking finish!


10.You Stripped or Cross-Threaded a Pipe or Fitting

This is a beginner mistake that can be avoided easily. You will know that something is cross-threaded when it feels impossible to tighten. Also, the threads will not align, and so it will look slightly crooked.


In order to keep this from happening, always make sure the screws go in without resistance before tightening with a tool. If you have trouble aligning the threads, remember this one little tip: Start counter-clockwise first, because that will get everything in place.


There you have it—10 common DIY plumbing mistakes! Now that you know some common issues, you are more prepared to tackle problems as they arise. But if a project becomes too hard to handle, don’t hesitate to contact a professional plumbing company.