The 10 Most Common Plumbing Mistakes DIYers Make

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By BenjaminBeck

You can fix most household plumbing repairs and even update plumbing fixtures with just a few special tools and a little elbow grease. The work isn’t physically challenging. But you do have to know the differences between the many types of pipes, fittings, glue and solder because that’s one big area where DIYers often mess up. In addition to not using the right parts, DIYers also make these other common mistakes. Here’s how to avoid the top 10 most common plumbing mistakes and get the job done right.

Overtightening Connections

Overtightening supply tubes, pipe and fittings and toilet bolts is the #1 DIYer mistake. If you crank too hard on a galvanized or black pipe, coupling, tee or elbow, you risk cracking the fitting. The crack may not happen right away, but the excessive force can break the fitting weeks later, causing a flood.

Overtightening the plastic fittings on toilet and faucet supply tubes is even more common. It just doesn’t take that much torque to seal a supply tube. If you tighten the hex nuts too much, they’ll eventually break and leak. Plus, overtightening toilet closet bolts at the floor or between the bowl and tank can crack the porcelain and destroy the toilet.

Wrapping Thread Tape Backward or Using the Wrong Tape

PTFE thread tape (commonly called Teflon tape) must wrap clockwise around the threads for it to work properly. But, many DIYers wrap it backward so the tape actually unwinds from the threads as they tighten the fitting. That defeats the whole purpose of using thread tape since it can’t seal if it isn’t embedded in the threads.

Here’s a tip for proper wrapping: Wrap three times around the threads with the last wrap facing to the left as you screw the pipe into the fitting. If that last wrap is pointing to the right, stop and re-wrap it.

Also, use the right tape.

• Use thin white or thick pink thread tape for fittings that carry water.

• Use yellow gas-rated tape for threaded gas line connections.

• Never use thread tape on compression or flare fittings

Using Drain Cleaners as a First Choice

The easiest way to remove kitchen and bath sink clogs is to use a snake or a barbed drain cleaning tool. Or, simply remove the P-trap and pour out the clog. But too many DIYers reach for the liquid drain cleaner first and they pour in way more than the recommended amount. That’s a mistake because liquid drain cleaner isn’t the best choice and more certainly isn’t better. In fact, liquid drain cleaner can create more problems than it solves. Here’s why:

• If the liquid cleaner doesn’t clear the clog, you or your plumber will probably have to remove the trap arm later on and it’ll be filled with caustic corrosive drain cleaner. Won’t that be fun?

• Using too much drain cleaner, or using it too often, can damage metal traps and pipes, causing leaks.

• Liquid drain cleaner destroys the rubber gasket used in “mission” style couplings. If you have any of those couplings in your drain lines and you use liquid drain cleaners, you’ll damage them, causing leaks in the future.