Any loss in shower water pressure is an annoyance, even if it’s just a short disruption due to a flushed toilet. And of course it’s much worse if it’s a chronic problem that makes it harder to rinse away shampoo and soap. There are several ways of fixing and preventing this common problem, but they vary depending on the root cause.
Pressure Balancing Valve Limitations
If your shower has a pressure balancing valve — where there’s a single knob or handle to control both the temperature and flow of water — you’re probably at risk of water pressure interruptions due to the use of other nearby fixtures. The classic example is when a flushing toilet causes both a water temperature change and a drop in pressure.
This type of valve mixes hot and cold water together at a certain pressure level. When the toilet flushes, cold water is diverted to refill the tank, which causes a pressure drop in the cold water line. It takes a pressure balancing valve a couple of seconds to adjust, during which time the water may turn very hot because the valve isn’t getting all the cold water it needs. And then when the valve does adjust, it does so by reducing the pressure coming from the hot water line, resulting in an overall drop in pressure.
Fortunately, there’s another type of shower valve that allows you to avoid this problem entirely. It’s called a thermostatic mixing valve, and it offers separate controls for water temperature and pressure. Call your trusted plumber to ask about upgrading to one of these valves.
Malfunctioning Diverter Valve
If you have a bathtub and shower combo, you probably have a diverter valve — a knob or switch that diverts water from the bathtub faucet up to the showerhead. These valves can malfunction or break after so many years of service, and the result could be that the valve can’t open enough to send full water pressure to the showerhead.
This is a likely culprit if water flows from the bathtub faucet at full pressure but fails to match that pressure from the showerhead. A plumber can confirm this diagnosis and complete the repair with a replacement diverter valve.
Water Pressure Reduction Valve Needs Adjustment
When your water pressure problem affects all of the fixtures in your home, the cause could be close to the water source. In some homes, a device called a water pressure reduction valve is connected to the main water line near the point where it enters the home. This valve can malfunction, break or fall out of adjustment — and all three are jobs for a professional plumber.
Broken or Obstructed Pipe
The worst possible cause of a shower pressure drop is a broken pipe, since the resulting leak could do serious damage to an unseen area of your home. If you can hear water running when and where it shouldn’t be, or if you suddenly notice dripping or water stains, shut off your water supply at the main valve and call a plumber for emergency service right away.
Clogged Pipe or Showerhead
On the other hand, the best case scenario is that your showerhead is simply dirty and clogged. To get a close look, unscrew your showerhead from the wall if possible. You may want to soak it in an appropriate cleaning solution for several minutes before cleaning all the nozzles thoroughly with an old toothbrush.
If you live in an area with hard water, you may also have mineral deposit accumulation inside your pipes. This reduces flow gradually and will eventually have a noticeable effect on water pressure. This problem can be avoided with the installation of a water softening system, but pipes that are badly clogged may need to be professionally cleaned or replaced.