You turn on a faucet and get a trickle instead of a steady stream. Your dishwasher takes forever to fill up and run a cycle. Showering becomes a struggle as there’s barely enough water to rinse the soap and shampoo away. Should you be worried about your water pressure?
While your water pressure could be to blame for many of these undesirable outcomes, low flow issues can occur due to many other factors. Rust could accumulate inside old, galvanized pipes, reducing the pipe’s diameter and restricting water flow; The faucet or faucet aerators could be partially blocked up and need a good cleaning; Who knows? But one thing is sure: whether individually or together, these elements could have a massive impact on your home’s water flow rate.
But what exactly is water flow rate? Isn’t it the same as your water pressure? What is the typical home water flow rate, and how do you measure your household’s water flow rate? Keep reading as we answer all these questions and others, such as what flow rate you should aim for in your home and what you can do to boost your flow rate when it is too low.
Home Water Flow Rate vs. Water Pressure – What is the Difference?
Water flow rate refers to the amount of water being used or coming out of a pipe or faucet in a particular time interval, measured by the gallon used per minute (GPM). It could also be defined as how much water is flowing out of the faucet at any given time. If you have a tap or appliance with a low water flow when activated or want to experiment and find the GPM of your kitchen tap or bathtub, we explain a simple method below to help you measure your home’s water flow rate.
While water flow is how much water comes out of your faucet within a specific period, water pressure is the amount of force or strength used to push the water through the tap. The water pressure is how hard the water moves from one point to another, like from your faucet into your drinking glass or water bottle. Typically, water pressure is measured in pounds per square inch (psi).
While water pressure can significantly affect your water flow, low water flow does not necessarily mean low pressure. As we mentioned earlier, other factors can influence a home’s water flow rate than just water pressure. A household’s flow rate and water pressure can change depending on the size of the house, the pounds per square inch needed to reach a fixture or appliance, etc. Let us discuss these and other factors in more detail.
Factors That Can Affect Home Water Flow Rate
Your water flow rate depends on various factors, from your household size to buildup in fixtures and pipes. While each may have varying levels of impact on your flow rate, the size of your household is the main culprit behind any low flow issues you may be dealing with, so let us begin there.
Number of Household Members
The average number of people living in a household is around two to four. A household size above four people is considered a “large household.” Living in a large household sometimes sets the stage for water flow problems. Water flow issues in large households often crop up when many people in the house have several intensive, water-using fixtures on simultaneously, causing a pressure drop in your home system, resulting in lower flow rates across the board. However, a large household does not mean you are guaranteed to experience low water flow. Many other factors can hamper your flow rate than just your household size, such as those described below.
The Square Footage of Your Home
Another factor that can make or break your water flow rate is the square footage of your home. Square footage is the amount of space in your home’s living area in square feet (sq. ft.). If your home has square footage above the standard 2,322 sq. ft., the water will need to travel a greater distance to reach your faucets, showerheads, appliances, etc. As a result, you will need longer pipes and a higher pressure to move the water along and ensure it reaches its destination.
The problem with longer pipes is that the flow rate varies inversely to pipe length. If you double the pipe length, you will get half as much water through it per unit time. But couldn’t homeowners with larger households increase the water pressure to make up for the households’ size and pipe length? Yes, but consider that higher water pressure could cause a lot of expensive damage to pipes and water-using appliances, including water heaters, washing machines, dishwashers, and toilets, causing them to stop working correctly because of the stress on plumbing and other parts. Plumbers suggest a maximum water pressure of 60 psi for average residential households, so homes above the average square footage could experience decreases in flow rates over time.
Low Water Pressure
As mentioned earlier, water pressure problems will affect the flow rate. If most of the fixtures and appliances in your home are experiencing low flow rates, your water pressure is low. Low water pressure can occur due to several factors, including:
- Problems with a water pressure regulator or a partially closed shutoff valve or meter
- Blockages in pipes, fixtures, and appliances
- Interior pipe deterioration
- Mineral buildup in pipes
- Water main breaks, leaks, and other issues in the public water distribution network
Blocked Pipes, Fixtures, Or Appliances
Low water flow rates can still occur even in a regular-sized home with two people and normal pressure. Blockages in pipes or fixtures, often caused by mineral buildup from hard water and constriction due to iron corrosion in pipes, can restrict the water flow, causing low flow rates. Sediment buildup in water heater systems can also cause massive drawdowns in hot water flow. Sediment, including dirt, debris, sand, rust, etc., can accumulate in your hot water tank over time. Eventually, this buildup will disrupt the hot water pressure in your home. So, if your hot water pressure seems abnormally low, sediment may be the issue.
Plumbing Size
The diameter of plumbing pipes can also influence water flow into and throughout a household. The larger the pipe’s diameter, the greater the water flow. For example, the flow rate of a 3/4” pipe is approximately 13.5 gallons per minute, while a 1” pipe flows at a higher rate of 21 gallons per minute.
How To Calculate Your Home Water Flow Rate: A Simple Flow Rate Formula
The easiest way to get a correct measure of your water flow rate is to time how long it takes to fill a container at an individual tap or plumbing fixture. You will need a measuring container for this method, such as a five-gallon bucket, a one-gallon water bottle, or a measuring cup.
Here are the steps to calculating your home water flow rate:
- Start by placing the empty container under the faucet.
- Open the tap entirely while starting the stopwatch. Stop the watch time when the container is full and turn off the water.
- Calculate the flow rate using this simple flow rate formula: 60 ÷ [Seconds to Fill] × [Gallons Measured] = GPM
- If you measured the water quantity in cups (U.S.), multiply the measured cups of water by six to obtain the total number of cups the faucet would fill up in a minute. Finally, convert the total number of cups filled in a minute to gallons (1 cup equals .0625 gallons).
Check out these examples you could follow to calculate your flow rate using the flow rate formula outlined above:
Example 1: Using a gallon container
If you fill a one-gallon container in 30 seconds, plug the number of gallons measured and the number of seconds it took to fill the container into the flow rate formula above:
You took 30 seconds to fill a one-gallon container, so your flow rate would be:
60 ÷ 30 × 1 = 2 GPM
Example 2: Using a measuring cup
If you filled 8 cups of water in 10 seconds, you would need to convert the cups to gallons first:
8 cups x 6 = 48 cups
Since 1 cup = .0625 gallons, the next formula is 48 x .0625 = 3 gallons.
So, your water flow rate would be 3 gallons per minute (3 GPM).
Once you obtain your water flow rate at a specific faucet, you can then compare it with standard flow rates for various fixtures for the typical home in the U.S.
Calculating your service flow rate
To calculate your service flow rate, add the flow rates for fixtures and appliances that may run longer than 10 minutes. Service flow rate refers to your everyday water flow.
Calculating your peak flow rate
To calculate your peak flow rate, add the flow rates for the maximum number of fixtures and appliances that may run simultaneously or install a water meter at the source to display exactly how much water is flowing per minute. The peak flow rate measures the maximum water flow. If every shower, toilet, or appliance were in use at your home, water would reach its peak flow rate.
If you check your peak flow rate at separate times of the day, especially at times when you think the most amount of water is being used, like first thing in the morning when everyone has a bath or shower, flushes the toilet, and so on, then this will give you the best sign of the peak amounts of water use and the number of liters per minute your household consumes.
How Many Gallons Per Minute Does Your Home Need?
The average flow rates in a standard American household vary based on the fixtures in question. The typical GPM usages of some common household fixtures and appliances are:
- Toilets: 2.0-3.0 gallons per minute
- Shower: 1.5-3.0 GPM
- Bathtubs: 4.0-8.0 GPM
- Bathroom or kitchen faucet: 2.0-3.0 GPM
- Dishwasher: 2.0-4.0 GPM
- Washing machine: 3.0-5.0 GPM
Compare the flow rate you calculated at various faucets in your home to these standard measurements to determine whether your flow rate is low, normal, or high.
If all your faucets and appliances were running simultaneously, how much would your GPM be? The typical residential water flow rate for small households is between 6-12 gallons per minute, so unless you plan to add extra kitchens, bathrooms, or laundry rooms to your home in the future, your home will never need to exceed that final GPM, assuming your flow rate is already normal.
Then again, when you start running more than one fixture at a time, the gallons per minute add up quickly. If you have a water softener or a particular water treatment unit that restricts flow, you may see a pressure drop when several fixtures run simultaneously.
Why Flow Rate is Important for Home Water Treatment
Finding your desired flow rate is crucial to picking the best water treatment system for your home. Whether a carbon filter, UV system, or water softener, your flow rate often serves as a rough guide for choosing the most suitable water system for your home appliances and fixtures.
When shopping around, look for a water treatment system that can handle at least 5 GPM, then consider the type of system you want and what contaminants you want to eliminate from your water. Do you want a system that filters from just your kitchen faucet? Or do you want it to filter across your whole home? Are you looking to filter out chlorine/chloramines, or do you also want to combat mercury and fluoride?
An under-sized system could lead to unsatisfactory water pressure and flow to the rest of the house, even if the incoming water pressure is high. Likewise, an oversized system could cause excessive pressure, causing damage to household plumbing, fixtures, and appliances.
A high flow rate can also be a massive issue for water filtration as it could also significantly reduce the contact time with filter media. The faster the flow rate, the less contact time dirty water has with the filter media and the less effective the filter. Water must have adequate contact time with the media to remove impurities while it passes through.
UV water purification systems work similarly. Disinfection is directly affected by the amount of contact time the UV light has with the water. Usually, water flows through a filter too fast because the system is not sized according to the proper flow rate. You may need a flow restrictor to slow the flow and increase contact time.
Ensuring Maximum Flow Rates in Your Home
The first way to ensure maximum flow rates in your home is to have good water pressure. Although low pressure is not always the culprit behind water flow issues in residential households, there are many ways to fix low water pressure at home and improve your flow rate.
Limited GPM in your home can also stem from the actual pipes in your home. If you still have galvanized pipes in your home and experience low flow, it is time to replace them because rust and other minerals are likely to accumulate in the pipes, causing corrosion and clogging and restricting water flow throughout the house. If the low flow only occurs at one faucet, the faucet aerator needs proper cleaning or replacement.
If the issue involves iron in the water, a whole-house water filter can quickly remove the iron and reduce the possibility of iron deposit buildup in the pipes. Similarly, a water softener can remove hard minerals from water known to cause mineral buildups in pipes, plumbing fixtures, and appliances. This buildup often restricts the amount of water that can travel through the pipes to faucets, fixtures, and appliances in your home, whether due to iron or hardness.
Another issue that can cause flow rate and pressure problems is an improperly sized filter. If you have a point-of-use water filtration system that filters out impurities like iron and sediment, the GPM that your house can support may be a bit lower. Fortunately, this is an easy fix. You need to replace the filter with one that can support a more substantial water flow.
Final Thoughts
Dealing with low home water flow is no fun. Everything from soaking in a bathtub after a long day to washing dishes and doing laundry will become longer, more frustrating tasks when your water flow is diminished. Luckily, you can do many things to increase your home’s water flow, like fixing water pressure issues, replacing your pipes, cleaning your faucet aerators, etc. But one of the most effective solutions is installing a whole-house system to remove iron or other contaminants that can accumulate in pipes and fixtures.
The WS1 Whole-House Iron Filter is designed and tested to reduce pollutants up to 12 gallons per minute (up to 20 GPM with the WS4). The same with the standard CF1 Whole-House Filter System – designed for contaminant reduction up to a flow rate of 9 GPM, up to 20 GPM using the more powerful CF4, and a whopping 20 GPM with the superior CF+. You can also add a water softener to eliminate hard minerals from blocking up your water heater, pipes, and household plumbing, thus increasing your water flow.
If you want to learn more about our water filtration and softening systems and how they can help improve your water flow, we would be happy to help. Please call us at 800-589-5592 or send us a message via our contact page.
