Last Updated: October 14, 2026 — Reviewed by Brian Hayes

Have you ever experienced loss of water pressure in the shower? If you have, then you know how troublesome it is – even if the cause is as simple as a flushed toilet. What makes it much worse if the problem is chronic and it makes it quite impossible to rinse away soap and shampoo. However, there are different ways to fix and prevent this common problem, and the solutions vary, depending on the different root causes.

Malfunctioning Diverter Valve

If you have a shower and bathtub combination, you probably have a diverter valve. This is the switch or knob that diverts water from your bathtub faucet towards the showerhead. These valves malfunction due to wear and tear, and this can result in the valve not opening enough to send full water pressure to the showerhead. Expert plumbing professionals can confirm this diagnosis and fix the problem with a replacement diverter valve.

Pressure Balancing Valve Limitations

If your shower has a single knob or handle that controls both the temperature as well as the flow of water, it means your shower has a pressure balancing valve. This puts you at risk of water pressure interruptions caused by the use of other nearby fixtures. A classic example of this is when a flushing toilet causes both a drop in pressure and a change in the temperature. Fortunately, there is another type of shower valve that lets you avoid this problem. This is called a thermostatic mixing valve. It offers separate controls for water pressure and temperature.

Broken or Obstructed Pipe

The worst possible reason for a pressure drop is a broken pipe. This will result in leaks that could do serious damage to unseen areas in your home. If you hear water running where it should not be, of if you notice dripping or water stains, then you should shut off your water supply at its main valve and call one of your experts right away. This is an emergency plumbing concern. If you suspect a hidden leak, our leak detection and repair service can pinpoint it before it damages walls or floors.

Clogged Pipe or Showerhead

The best case scenario is that your showerhead is just simply clogged or dirty. If you live in an area that has hard water, you can also have mineral deposit accumulation inside the pipes. This gradually reduces flow and you will eventually notice an effect on your water pressure. This can be solved simply by installing a water softening system. Pipes that are clogged badly might need to be cleaned or replaced professionally.

If you cannot track down the source of your water pressure problem, then give us a call today!

Additional Resources

Frequently Asked Questions

Why does my shower pressure drop when a toilet flushes?

A shower with a single knob that controls both temperature and flow has a pressure balancing valve, which can be affected by other nearby fixtures. A thermostatic mixing valve, with separate controls for pressure and temperature, avoids the problem.

Can a faulty diverter valve cause low shower pressure?

Yes. In a shower and bathtub combination, the diverter valve sends water from the tub faucet to the showerhead. These valves wear out and may stop opening enough to send full pressure to the showerhead, but a replacement diverter valve can fix it.

Could a pressure drop mean there is a hidden leak?

Yes, a broken pipe is the worst possible cause of a pressure drop. If you hear water running where it should not be, or notice dripping or water stains, shut off your water at the main valve and call a plumber right away. Our leak detection and repair service can pinpoint hidden leaks.

Need help with your bathroom renovation? Hayes Plumbing & Bathroom Renovations serves Oshawa, Ajax, Whitby, Clarington, and Pickering. Contact us or call (905) 576-3043 for a free estimate.