If you’ve ever tried to take a shower while the washing machine is in use, and discovered that only a trickle of water would come out of your shower head, you’ve probably dealt with low water pressure.
It’s natural for your home’s water pressure to drop when multiple appliances are being used at once. But some homes may have a lower water pressure than others, and this can lead to problems, especially if you have a family of four or more.
In this guide, I’ll be sharing the typical household water pressure, and what can cause water pressure to drop.
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🆚 Water Pressure vs Water Flow Rate
First off, it’s important to understand that water pressure and flow rate aren’t the same thing. While these terms are often used interchangeably, they are actually different measurements.
The flow rate of your water is the amount of water that flows out of your faucet within a specific time period. Flow rate is measured in gallons per minute, or GPM, and essentially indicates how much water could leave a faucet in your home at a given time.
Water pressure isn’t determined by speed; it’s determined by gravity. Your home’s water pressure is the force applied to the water in your pipes to get it to where it needs to be.
Your water pressure affects your water flow rate. The lower your water pressure, the slower the flow of water through your faucets.
📋 What Affects Average Residential Water Pressure?
There are several factors that can affect your home’s water pressure, including leaking pipes, scale build-up, a failed pressure regulator, and more.
A leak in a pipe leading up to your home may cause a loss of water pressure. You may not notice that a pipe is leaking, especially if it isn’t inside your home, but the gap created by the leak can cause pressure to escape.
If you think you have an issue with leaking pipes, it’s wise to call a plumber for a professional evaluation. A leak in your main water line presents the risk of microbiological contamination, and you certainly don’t want to be drinking bacteria, viruses or protozoa in your water.
Scale build-up is a very common cause of reduced water flow rate. Even if your water pressure itself hasn’t dropped, scale can affect the flow of water through your pipes, creating friction and dragging the water back.
You can remove scale from your pipes using a scale removal solution, but be aware that it will eventually come back if you have hard water.
The best way to prevent a build-up of limescale is to use a water softener. This will remove the limescale and magnesium responsible for water hardness, eliminating scale formation entirely.
Pressure Regulator Has Failed
Another common water pressure issue is linked to the pressure regulator or PRV, pressure-reducing valve itself. If this regulator becomes faulty, it might not properly control the input pressure in your plumbing system.
Not all homes have a regulator for water pressure, but if yours does, and you’ve noticed that your water pressure has suddenly dropped, it’s worth checking that everything is in order. In most cases, you will need to call a professional to replace the regulator for you.
Water Meter Valve Isn’t Open
Most homes have two water shutoff valves that are used to control water flow into your home. The first of these valves is the water meter valve. You can find it near to your water meter on the water line leading into your home.
You usually won’t have to touch this valve, as it’s technically the property of your water supplier. However, if your water pressure is low, it’s worth checking this valve to see if it isn’t fully open. This is especially worth doing if you have recently had some plumbing work done around your home.
If the plumbing in your home is old and worn, corrosion may be causing a drop in water flow.
As with limescale, corrosion in your plumbing won’t affect your water pressure itself, but it will slow down your water flow rate in gallons per minute.
Corrosion is most likely to be a problem in a household with galvanized steel water lines. Corrosion can build up in the water system, eventually restricting water flow.
You won’t notice a sudden drop in your water’s flow rate in this case; the problem builds up gradually over a number of decades. The only suitable solution is to re-pipe the plumbing and fixtures in your whole house, which can be quite an expensive job.
Time of the Day
There may be certain times in the day when there’s an increased demand for appliances in your home that use water.
A common time for water pressure to dip is from 7 am to 9 am, when people typically get ready for work and school. Showers, washing hands, and perhaps even a last-minute washing machine cycle can all contribute to decreased water pressure when they occur simultaneously.
You may also experience pressure drops in the evening, when you might be using the dishwasher and washing machine at the same time as following a bathtime-bedtime routine with your children.
📌 What is the Average Residential Water Flow Rate (GPM)?
Most small households in America have an average water flow rate of around 6 to 12 gallons per minute (GPM).
It’s difficult to determine a daily flow rate per household, as it depends on factors such as the number of people in your household, the newness of your plumbing and appliances, the amount of water you use per shower, and so on. A general estimate for most homes is between 100 and 120 gallons per day.
Of course, having a large household doesn’t automatically mean that your home water usage will be higher. However, it does mean that there’s an increased chance of more people using water in your house at the same time, which might affect how much water is used at certain times in the day.
Flow Rate & Square Footage
Aside from your family size, the square footage of your house can affect your water pressure, and the flow rate of water in gallons per minute.
Most households have an inlet water pressure of 40-45 PSI (pounds per square inch). A standard household shouldn’t exceed 80 PSI, as this could damage your plumbing, fixtures and appliances, including your water heater. This is why a plumber will usually regulate a household’s water pressure to about 50 PSI.
However, if your home’s square footage is larger than the average house square footage in the US (just over 1,300 sq. feet), then it won’t be classed as a “standard” household. You might need to reconfigure your water pressure to up to 75 PSI if your flow rate is low. I would recommend consulting an expert before increasing your water pressure to stay on the safe side.
❔ How Do You Calculate Water Flow Rate?
How many gallons per minute (GPM) of water does your own house use? We know by now that flow rates can vary from one house to another, so knowing your own exact flow rate will prove useful.
It’s relatively easy to calculate your home’s flow rate in GPM per faucet. Simply turn your faucet all the way on and hold a measuring jug beneath the running water for 10 seconds.
When the time is up, remove the measuring jug and look at how many gallons of water the jug contains. Next, multiply this amount by 6, which will calculate the number of gallons per minute your whole house water system can produce.
To know whether your flow rate is higher or lower than the typical flow rate in the US, compare to the following figures:
- A kitchen faucet usually has a flow rate of between 1.5 and 3 gallons per minute
- A shower has a flow rate of approximately 2.5 to 3 gallons per minute
- A dishwasher operates at between 1.5 and 3 GPM
- Washing machines have an average flow rate of 2 to 4 GPM
Judging by these average flow rates, you should expect your water pressure to drop if you were using these four appliances at once.
🧠 How Many Gallons Per Minute Do I Need for My Home?
A minimum flow of 6 GPM is recommended for most standard households. For most people, this GPM will be high enough to meet water usage requirements, even when water is in peak demand. However, the exact GPM for your household will depend on your home water usage, and whether you plan to use appliances that may slow down your flow rate.
For instance, if you intend to use a whole house water filter to remove contaminants from your drinking water, your flow rate in GPM might decrease slightly. This is because water meets resistance from the filter media, which prevents it from flowing freely through your plumbing.
This doesn’t mean that you should adjust your water pressure too high, though, as elevated flow rates can be both dangerous to your home and damaging to your water filter.
It’s best looking instead for filters with flow rates of at least 5 GPM or more – preferably those with an NSF certification, so you know they’ll live up to expectations. You could also consider a filter system that wouldn’t affect your whole home’s flow rate, such as a point-of-use filter.
If you think your home’s flow rate is far too high or too slow, I recommend calling a licensed plumber to assess your situation, rather than attempting to remedy the issue yourself.