Ask Pete: Why Are My Pipes Knocking When I Flush The Toilet?

If you hear a knocking sound every time you flush the toilet, you might feel concerned about a possible plumbing issue. This noise, also called a “water hammer,” often sounds like someone is knocking on the walls of your home every time a person flushes the toilet. It might seem like this is a huge plumbing issue that needs immediate professional help. But, lucky for you, a “water hammer” is usually a simple fix that can and should be done quickly. 

Why Are My Pipes Knocking When I Flush the Toilet? 

When you flush the toilet, that annoying knocking noise is most likely coming from your pipes knocking against the wall. Why do they knock against the wall? When you flush your toilet, water quickly rushes through your pipes to a water fill valve that opens to refill your toilet with water. When that valve closes, the rushing water slams against the valve and creates a pressure buildup. All this pressure is what causes your pipes to knock against your walls.

How do I Stop My Pipes from Banging When I Flush the Toilet? 

As I mentioned earlier, stopping your pipes from banging when you flush the toilet is a pretty simple process for any plumber. But it’s something that should be done quickly. Not addressing this problem in time can lead to a breakdown of your pipes from too much pressure. You know that this has happened when you can hear knocking any time you use water, not only when you flush the toilet. If you’re experiencing this, you should contact a professional immediately. 

Fixing your problem will depend on when your home was built. Homes built before the 1960s used air chambers that blocked water hammer. Unfortunately, these air chambers do deteriorate quickly. Homes built between the 1970s and 1990s had no protection against water hammer. More often than not, you’ll need a professional plumber to come in and install water hammer arrestors. These are small devices that are meant to protect against water hammer.

Most modern homes use water hammer arrestors. If your home was built after the 1990s and you’re hearing knocking, your home either doesn’t have any water hammer arrestors or something else is going on. 

Can I Fix Knocking Pipes by Myself? 

Even though the solution to your knocking pipes is simple, it’s still a professional job that needs to be handled by an experienced plumber. This is especially true if you have a newer home or have been experiencing the problem for a long time because these are possible signs of other issues at work. A professional plumber will be able to fix your problem easily and let you know if there’s anything else going on with your pipes. 

Get A Free Estimate

Phend Plumbing is your local plumbing specialist in the Phoenix Valley area. With offices in Mesa-Phoenix and Gilbert, Arizona, our family-owned business has years of experience helping homeowners and businesses with all their plumbing needs. We offer up-front pricing and fast, professional work. Give us a call at 480-388-6093 or contact us online to get a free estimate on your next plumbing project today.