You stand under the shower and the pressure feels weak. Is there a way to fix low shower water pressure? Corroded water pipes may be the ultimate culprit. But there might be any number of other causes that are easier to address than ripping out all of the pipes in your house. To get started, first determine if you really do have low shower flow by conducting a simple test to measure the flow in gallons per minute (gpm).

What You’ll Need
Equipment / Tools
5-gallon bucket
Stopwatch or timer

Materials
White vinegar
Toothpick
New shower head (as needed)

Test the flow of shower head

Turn on the shower to its maximum capacity. Let it run for about a minute. Place a 5-gallon bucket under the water stream and determine how long it will take to fill the bucket. Once the water hits the bottom of the bucket, it starts to count, and immediately stops the count when the water starts to overflow the bucket.

To calculate gpm, start at 5 and divide by the time required to fill the bucket. For example, if the time is 2.5 minutes: 5 divided by 2.5 = 2. The flow rate is 2 gpm.

For reference, the following is the standard benchmark for gpm traffic:

1.5 gpm: standard flow rate of low flow nozzle
2 gpm: current US federal WaterSense standard
2.5 gallons per minute: the maximum flow rate of all shower heads in the United States, established in 1992

Replace Your Water-Restricting Shower Head
If you have a low-flow shower head, or install a shower filter or water-saving device in an ordinary shower head, the shower flow will be reduced to a minimum. Based on your current flow rate, you can increase the flow simply by removing the filter or throttling device or changing the nozzle to a high-flow model (for example, to a standard 2.5 gpm nozzle).

Before replacing the shower head, please make sure that the new model is legal in your area. For example, in California, shower head flow has been shrinking for decades due to the state’s ongoing drought. The shower head first rose from 2.5 gpm to 2.0 gpm, and then to 1.5 gpm.

Remove Scale Buildup
Over time, mineral deposits and limescale can clog your shower head. This is not a question of “if” but a question of “when”, because all tap water contains minerals.

To remove scale on the shower head, unscrew and soak it in a bowl of white vinegar for at least eight hours. Then, use a toothpick to remove all residual particles in each spray port. Reinstall the shower head and spray water sufficiently to check the flow.

If the deposits are not easy to remove, it is time to buy a new shower head.

Check the Curb-Side Main Shutoff
In some cases, because the main power on the curb side is not fully turned on, you may have been in a low water pressure state throughout the house. Due to the large structure in the house, it may have been closed and then not fully opened.

The place where the water main enters the roadside is the water meter and the shut-off valve. Check to make sure the valve is always open. If the valve has a round handle (such as a hose bib), it should be turned fully counterclockwise. If there is a lever-type handle, the lever should be parallel to the water pipe.

Generally, you are not allowed to tamper with the water meter on the roadside site, so if you need to dispose of the water meter itself, please call the water supply company. They will send a worker to check for you.

Check the Main Shutoff in the House
A more likely way for a previous homeowner or worker to lower your water pressure is to lower the main pressure value of the water after entering your house.

There may be multiple reasons. If the previous owner rented a house, they might turn down the volume in an attempt to force residents to use less water. Or, like the main power supply on the curb side, it may be turned off due to water leakage or construction, but accidentally not fully turned on again.

Carefully turn the house shut-off valve counterclockwise (for round handles) or parallel to the water pipe (for lever handles). The valve may be corroded and rusted; do not force it.

Replace Your Single-Handle Volume Control
Another item that influences a shower’s water pressure is the volume valve system on a single-handle shower faucet. This is a rather pricey and complicated part that, over time, may compromise your water flow. Because these are difficult to repair, replacement is usually the best option.

Open Up In-Line Shut-Off Valves
Some homes have an in-line shutoff valve on the water lines supplying the shower head, similar to those found on sink supply lines. These valves are on individual branch pipelines and they act as emergency stops. They are convenient if you are doing work in a local area (shower, toilet, sink, etc.) and do not wish to shut off the water in the entire home.

These shutoff valves, if you have them, are likely to be located near the supply point. For a shower that has supply pipes in the basement, these shutoffs would be located on the pipes leading up to the shower.

As with the main water shutoffs, it’s possible that small fixture valves are not fully open. Turn these valves counterclockwise all the way for full pressure.