When you turn on a faucet or use appliances like your washing machine, you likely don’t give too much thought to how fast the water flows out of your fixtures. But when household water pressure changes, it’s immediately noticeable. Maybe your water only trickles out of the showerhead or your dishwasher is filling very slowly. In times like these, it’s important to be familiar with water pressure and flow rates so you can maintain a comfortable, efficient home.
Water pressure and flow rates are key factors that impact your home’s water usage and costs in addition to your plumbing, fixture, and appliance performance. Knowing the signs of low water pressure and flow rate can help you quickly address these issues. Understanding these characteristics is also important if you have a water filter installed or are thinking about purchasing one, as fitting your home with the right filter for your home’s flow rate can help mitigate some issues that contribute to low water pressure.
What Are Water Pressure and Flow Rate?
Water pressure is the measurable force exerted to propel water through pipes to fixtures. This pressure is measured in pounds per square inch (psi). Water pressure directly affects flow rate, since flow rate is the amount of water that comes out of a fixture in a particular period of time. Water flow rate is calculated in gallons per minute (GPM).
What Is the Average Home Water Pressure and Flow Rate?
Normal residential water pressure typically falls somewhere between 45 and 80 psi. Any measurements under 40 psi are considered low. When it comes to flow rates, anywhere between 6 to 12 GPM is average. Homeowners should want their water to fall within these standard ranges. While you might think having high water pressure is a good thing, it can actually be damaging to pipes, fixtures, appliances, and filters. However, low water pressure is generally more common than high water pressure.
Is Well Water Pressure Different From City Water Pressure?
Most homes that rely on municipal water from a city receive water at about 60 psi. Default settings on well pressure tanks are usually set quite low; they can sometimes be lower than 30 psi. However, these settings can be adjusted to increase well water pressure. If you use a well for your water, you’ll probably need to pay closer attention to your water pressure settings to ensure your home falls within normal pressure ranges. Both wells and city water can supply homes with an acceptable, average home water pressure.
Signs of Low Pressure
Fortunately, it’s fairly easy to recognize signs of low water pressure in your home. Some of these signs include:
- Fluctuating water speed from fixtures when using more than one faucet at a time
- Varying water speeds from every fixture or appliance in the home that uses water
- Decreasing water fill speeds or increasing cycle speeds for appliances
- Reading water pressure gauges at or below 40 psi
What Causes Low Pressure and Flow Rate?
While it’s easy to see when the flow rate is low, diagnosing why water pressure is low is a little more complicated because there are so many contributing factors, such as:
- Excessive water use in a short period of time (e.g., having long showers back-to-back while running a dishwasher or washing machine at the same time)
- An above-average size house, which causes water to travel farther to reach fixtures
- Blockages in pipes, fixtures, or appliances which can be caused by sediment, corrosion, and mineral deposit buildup
- Partially closed main water valve or water meter
- Incorrectly set or failing pressure regulator
Necessary Flow Rates for Common Fixtures and Appliances
In 1992, the U.S. government set regulations on flow rates for fixtures such as faucets and showerheads as well as toilets. Fixtures manufactured after these mandates cannot exceed federal flow rate maximums, though older fixtures made before these regulations can. Therefore, the necessary flow rates listed below account for both newer and existing fixtures:
- Kitchen and bathroom faucets: 1.0-3.0 GPM (max 2.2 GPM for newer fixtures)
- Showerheads: 1.5-3.0 GPM (max 2.5 GPM for newer fixtures)
- Toilets: 1.0-3.0 GPM (max 1.6 GPM for newer models)
- Dishwasher: 2.0-4.0 GPM
- Washing machine: 3.0-5.0 GPM
Flow rates below these metrics indicate insufficient water pressure, while flow rates above these standards may lead to high water costs and affect performance.
How to Check Water Pressure At Home
Checking your water pressure at home is fairly simple. First, turn off all appliances, faucets, and fixtures that use water, as they can alter pressure readings. Next, you’ll need to attach a pressure gauge to a spigot or faucet. If you have city or municipal water, choose the hose spigot closest to your home’s main water supply line. If you have well water, attach the gauge to a hose bib or faucet close to the well pressure tank. After the gauge has been tightened and the faucet is completely open, read the psi. Remember, anything below 40 psi or higher than 80 psi indicates your water pressure is too low or high, respectively.
How to Calculate Flow Rate
Figuring out your home’s flow rate is even easier, and it doesn’t require any additional tools or equipment. All you’ll need is an empty gallon jug and a stopwatch or timer. Pick any faucet or showerhead in your home and place the empty gallon jug under it. Turn on the faucet and start your stopwatch at the same time to see how long it takes to fill the container. Once full, turn off the faucet and stop the timer simultaneously.
Let’s say it took 25 seconds to fill the 1-gallon jug. To calculate flow rate, you will need to divide the volume of the container by the time it took to fill the container. Since GPM is gallons per minute, you should also convert seconds to minutes. In our example, 25 seconds is equal to 0.4167 minutes.
So, 1 gallon / 0.4167 is roughly 2.4 GPM.
Impact of Water Pressure and Flow Rate on Water Filters
Water pressure and flow rate matter when it comes to water filters. If water pressure and flow rate are too high, water contact time with the filter media is reduced. The shorter the contact time, the less effective the filter is at trapping contaminants. If water pressure and flow rate are too low, water may not be able to pass through filter membranes. This is why it’s important to stay within appropriate water pressure and flow rate ranges so your water has optimal contact with filter media.
Kind Water Systems’ systems support flow rates up to 15 GPM. When paired with a salt-free softening, these systems also help combat hard water mineral buildup which can gradually reduce water flow rates, especially if you have smaller diameter pipes. If you have questions about how your home’s water pressure and flow rate might affect your water filtration options, work with professionals to find the right system.
