Why Is My Water Pressure Suddenly Low in My House?

Low water pressure can be frustrating. Whether you’re trying to take a shower, wash dishes, or fill a kettle, weak water flow can quickly become an inconvenience.

If your water pressure has suddenly dropped, it may be a sign that something in your plumbing system isn’t working as it should. Understanding the possible causes can help you decide when it’s time to call a professional plumber.

Common Causes of Low Water Pressure

1. Hidden Water Leaks

One of the most common causes of sudden low water pressure is a leak somewhere in your plumbing system.

Leaks can occur:

• Underground between the meter and your house

• Inside walls or under floors

• In outdoor pipes or irrigation systems

When water escapes from a pipe before reaching your taps, it reduces the pressure throughout your home.

2. Partially Closed Isolation Valve

Sometimes the problem is surprisingly simple. If the main water isolation valve near your meter or house is not fully open, it can restrict water flow and reduce pressure.

This can happen after plumbing work or maintenance.

3. Faulty Pressure Limiting Valve

Many homes have a pressure limiting valve (PLV) installed to protect the plumbing system from excessive pressure.

Over time, these valves can wear out or fail, which may cause:

• Sudden drops in water pressure

• Inconsistent flow from taps and showers

A plumber can test and replace a faulty valve if needed.

4. Blocked or Corroded Pipes

Older plumbing systems may develop internal corrosion or mineral build-up, especially in galvanised pipes.

This build-up restricts the internal diameter of the pipe, which can significantly reduce water flow throughout the home.

5. Problems with the Water Meter or Supply

Occasionally, the issue may come from the water supply itself. Maintenance work, local infrastructure issues, or problems with the meter assembly can sometimes affect pressure.

If several houses nearby are experiencing the same problem, the issue may be with the supply network.

How to Check for a Possible Leak

If your water pressure suddenly drops, it’s worth checking your water meter.

1. Turn off all taps and water-using appliances in the house.
2. Check your water meter reading.
3. Wait 15–30 minutes without using any water.
4. Check the meter again.

If the meter has moved, it could indicate a hidden leak in your plumbing system. If you are on town water, you may also wish to check the Unity Water outage guide here.

When to Call a Professional Plumber

While some simple checks can help identify the problem, ongoing low water pressure should be inspected by a licensed plumber.

A professional plumber can:

• Check for hidden leaks

• Test pressure limiting valves

• Inspect pipework for blockages or damage

• Diagnose supply issues

Plumbing Services in the Local Area

At Plumbing & Gas Services Pomona, we help homeowners diagnose and fix plumbing problems quickly and efficiently.

Our services include:

• Leak detection

• Water pressure testing

• Pressure limiting valve replacement

• Pipe repairs and replacements

• General plumbing maintenance

If your water pressure has suddenly dropped, it’s best to have it inspected before the problem becomes worse.

📞 Contact Plumbing & Gas Services Pomona today to arrange a plumbing inspection.