High Water Pressure: The Hidden Cause of Burst Pipes in Your Home
Most homeowners never think about their water pressure until something goes wrong. You turn on the tap, the water comes out fast, and life goes on. But here’s the problem — high water pressure is one of the most common causes of burst pipes, and most people have no idea theirs is too high.
Residential plumbing systems are designed to run at 40 to 60 psi (pounds per square inch). When that number creeps above 80 psi — which happens more often than you’d think in the North West — your pipes start taking damage they weren’t built to handle. And it’s not just one type of pipe that’s vulnerable. PVC, copper, and galvanized steel all react differently to pressure. We’ll cover each one.
What High Pressure Does to Your Pipes
Fatigue
Just like bending a paperclip back and forth until it snaps, high pressure puts your pipes through constant stress. Every time water slams through the system — especially when a tap closes suddenly — that pressure spike hits the pipe walls and joints. Over months and years, the material weakens. Then one day, it gives.
Joint Failure
Joints are always the weak point. High pressure strains the connections between pipes more than the pipes themselves. A fitting that’s holding up fine at 50 psi can start leaking at 75 psi. And a leak at a joint, left unchecked, turns into a burst.
Corrosion Acceleration
High pressure doesn’t just strain pipes mechanically — it also accelerates chemical wear. Water moving at higher speeds and pressure carries more oxygen and minerals against the pipe walls. For metal pipes, that means faster corrosion from the inside out.
How Different Pipe Materials Handle High Pressure
| Material | Max Safe PSI | How It Fails | Verdict |
|---|---|---|---|
| PVC | 60–80 psi | Warps, cracks at joints, bursts in cold weather when pressure spikes | Most vulnerable — needs pressure regulation |
| PEX | 80–100 psi | Fittings fail before pipe does — the pipe flexes but connectors don’t | Best option — flexible, resists pressure damage |
| Copper | 80–100 psi | Water hammer shock at joints, solder joint fatigue, pinhole leaks | Solid but vulnerable to hammer |
| Galvanized Steel | 60–80 psi (when old) | Internal rust narrows pipe, pressure builds behind blockage, burst at weak point | High risk — internal corrosion makes pressure unpredictable |
PVC and Plastic Pipes
PVC is lightweight, cheap, and easy to install. That’s why it’s everywhere. But it has a real weakness — it’s not built for sustained high pressure. PVC pipes start warping and cracking once pressure passes 80 psi, especially at the joints where the pipe wall is thinnest.
There’s a second problem too. In cold weather, PVC gets brittle. Combine that with a pressure spike from a closing valve, and you’ve got a recipe for a sudden burst. If your home has PVC supply lines — and many newer builds do — a pressure-reducing valve isn’t optional. It’s essential.
PEX Pipes
PEX is the most forgiving of the bunch. It flexes under pressure instead of cracking, which is why it’s become the standard for modern plumbing. PEX pipes can handle 80-100 psi without much trouble.
But PEX has a catch. The pipe itself handles pressure well, but the fittings — the brass or plastic connectors — don’t flex. Under sustained high pressure or repeated water hammer, the fittings are what fail, not the pipe. So even with PEX, pressure matters.
Copper Pipes
Copper handles higher pressure than PVC, but it’s not immune. Copper’s main vulnerability is water hammer — that banging sound you hear when a tap closes fast. Water hammer creates a shockwave that travels through the pipe and hits the joints with force far above normal operating pressure. Over time, those solder joints weaken and develop pinhole leaks. At high enough pressure, they burst.
Copper is also vulnerable to aggressive water — water with low mineral content that eats copper from the inside. High pressure makes this erosion worse, since the water moves faster and strips more material.
Galvanized Steel Pipes
Galvanized steel is the ticking clock of plumbing materials. It starts strong — the zinc coating resists rust, and the steel handles pressure well. But the coating degrades over 15-20 years. Once it’s gone, rust builds up inside the pipe, narrowing the passage. The water still needs to get through, so pressure builds behind the narrowing. Eventually, the rust-weakened pipe wall can’t take it anymore.
If your home was built before 2000 and still has galvanized pipes, high pressure isn’t just a risk — it’s actively accelerating the clock. Have a professional plumber inspect them before winter.
Best Practices to Prevent Burst Pipes from High Pressure
Monitor Your Water Pressure
You can buy a pressure gauge for a few hundred rand. Screw it onto an outdoor tap or washing machine connection, turn the tap fully on, and read the number. If it’s above 80 psi, you need a pressure-reducing valve. If it’s above 100 psi, call a plumber today — that’s emergency territory.
Install a Pressure-Reducing Valve (PRV)
A PRV is a simple device that screws onto your main water line and keeps the pressure inside your home at a safe level, regardless of what the municipal supply is delivering. It’s one of the cheapest and most effective ways to protect your entire plumbing system. Most plumbers can install one in under an hour. Worth every cent.
Fix Water Hammer
If you hear banging in your pipes when taps close, you have water hammer. It’s not just annoying — it’s damaging your pipe joints. Air chambers or mechanical water hammer arrestors can fix it. Or call a plumber to diagnose the cause. Ignoring it means slowly destroying your pipes from the inside.
Schedule Regular Inspections
An annual plumbing inspection catches the stuff you can’t see — early corrosion, weakening joints, pressure creep. It’s cheap insurance against a burst pipe that floods your home.
Upgrade Old Pipes
If you’ve got galvanized steel or old PVC supply lines, replacement isn’t just about convenience — it’s about safety. Modern PEX handles pressure better, doesn’t corrode, and costs less to install than copper. A full repipe sounds expensive, but compared to repairing flood damage from a burst, it’s a bargain.
FAQ: High Water Pressure and Burst Pipes
What is considered high water pressure in a home?
Anything above 80 psi puts your plumbing at risk. Ideal residential pressure sits between 40 and 60 psi. Above 100 psi? That’s an emergency — call a plumber.
Can high water pressure cause a pipe to burst suddenly?
Yes. A sudden spike — from a closing valve or a surge in the municipal supply — can burst a weakened pipe instantly. The joints are usually the first to go.
How do I check my home’s water pressure?
Buy a pressure gauge (R150 at any hardware store), screw it onto an outdoor tap, and turn the tap fully on. The needle tells you your PSI. If it’s above 80, you need a pressure-reducing valve installed.
Does a pressure-reducing valve stop all pipe bursts?
No — it prevents pressure-related bursts, but you can still get bursts from freezing, corrosion, or physical damage. It’s one essential layer of protection, not a silver bullet.
Need a Plumber in the North West?
High water pressure is a silent problem — you won’t notice it until something bursts. Tap Tap Plumbing offers emergency burst pipe repair, pressure-reducing valve installation, and full plumbing inspections across Potchefstroom, Klerksdorp, Stilfontein, Orkney, and Hartbeesfontein. No call-out fee, fixed pricing, and same-day service.
Don’t wait for a burst to find out your pressure is too high. Get it checked now.
Book a pressure inspection or emergency repair →
