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What Causes Low Water Pressure?

You may not realize how much you rely on water to accomplish all sorts of tasks until you run into a problem with your water supply. In the worst cases, some issues can leave you without access to water at all for a time. Even when your water is working, however, you may still experience issues from low water pressure. Low water pressure is when the water that comes out of plumbing fixtures, like faucets or shower heads, weakly dribbles out rather than sprays out at the speed and volume it typically does.

When your water pressure is low, it can greatly affect the quality of living in your home. Everything from showering, to washing dishes, to doing laundry and more will turn into longer, more frustrating tasks when your water pressure is diminished. To fix the issue, you need to understand the cause. In this post, we will look at several possible causes for a loss of water pressure in your home and what you can do to address the problem.

Understanding Water Pressure

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If your water comes from a municipal water provider, then it is pumped from a natural water source to a treatment facility where it then moves to pressure tanks at higher altitudes. A common example of this is a water tower. Gravity creates pressure naturally, so when your water comes to you, it is already pressurized. In some cases, booster stations help to maintain the pressure throughout the water lines in a city. If your water comes from a private well, then your water is pressurized through a tank that maintains a range of pressure.

Residential water pressure should ideally be in the range of 45 to 55 pounds per square inch (psi), but it typically ranges from 45 to 80 psi. A psi reading under 40 is considered low, and a reading under 30 is definitely too low.

Quick Start Guide for Diagnosing Low Water Pressure

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Before we discuss in detail several different potential causes for low water pressure, we will take a moment to give you a quick overview to help you get started. Here are several reasons why you may experience a loss of water pressure in your home:

  • Too Much Demand on Water: In some homes, having multiple plumbing fixtures on at once can place too high of a demand on the water supply for proper water pressure to be maintained in every fixture. With a little coordination, you can usually avoid this issue.
  • Faulty Fixtures: Fixtures themselves, such as shower heads or faucets, can become faulty or clogged over time. In some cases, simply cleaning out the screen or aerator is enough to fix the issue, but at other times, an entire fixture may need to be replaced.
  • Broken Pressure Regulator: Water pressure regulators are designed to help stabilize water pressure in your home, keeping it within a certain range. When these regulators go bad, your water pressure can either become too high or too low.
  • Closed Valves: Your home's water supply can be shut off by two different valves. You can check both of these valves on your own. If either of these valves is not fully open, then it can affect the water pressure throughout your home.
  • Clogged Pipes: If pipes become clogged, these blockages can disrupt water flow through your pipes. With the flow disrupted, water pressure will also go down. Pipes need to be cleaned out or replaced to address the issue.
  • Corroded Plumbing: Clogs can be fixed by cleaning out or replacing small sections of piping. Over time, though, your entire system of piping can become corroded, which can have a negative effect on your water pressure.

Keep reading for more detailed explanations on each of these issues and how to fix them. Remember that, in most cases, you will make your life much easier and avoid further complications by calling in a professional to address the problem.

How Many Locations in Your Home Have Low Water Pressure?

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When you are investigating an issue of low water pressure in your home, the first thing to note is the scope of the problem. In other words, you need to know how many plumbing fixtures are experiencing decreased water pressure. You may find the issue is only affecting one fixture, all fixtures in a certain room or every fixture throughout your house.

This is important information since it can help you trace what the issue might be. If only one fixture is experiencing low water pressure, then it may just need an easy fix related to that fixture alone. In other cases where water pressure is low throughout the house, it may indicate a more serious issue in your plumbing.

Go through the interior of your home and around the exterior to check each plumbing fixture, including:

  • Dishwasher
  • Sink faucets
  • Toilet
  • Shower
  • Bathtub
  • Washing machine
  • Outdoor faucet
  • Hose hookups

As you go to each fixture, turn it on and test both the hot and cold temperatures. Is the water pressure only low on the hot setting? Is it only on the cold setting, or is it low for both? If you find that water pressure is only low when a fixture is on the hot water setting, for instance, then the issue could lie with your water heater.

Most Common Cause of Low Water Pressure

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Often, when you experience a decrease in water pressure, it is because two different plumbing fixtures are on at the same time. For example, you might turn your shower on while your dishwasher is running and notice that the water coming out of the shower head is not as pressurized as usual. Or, you may notice that your washer is taking longer to fill up than normal while someone is running the hose outside.

This occurs because your water supply only has so much to offer at any given time. When you need a water flow in two or more places at once, the water has to divide rather than all going to one place, and this reduces the pressure. If dividing your water flow is the reason you are experiencing low water pressure, then your water pressure should go back to normal when you are no longer placing such a high demand on your water flow.

In the case of the weak shower, wait until the dishwasher is finished running, and try turning on the shower head again. In the case of the washer, turn off the hose outside, and see if the washer begins to fill up more rapidly. If everything goes back to normal when you are only using one plumbing fixture at a time, then you can enjoy good water pressure once more. You should still keep an eye on your water pressure, however, to see if it eventually drops too low, as this could indicate a problem that needs to be fixed.

Additional Reasons for Low Water Pressure

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In some cases, it is not as simple as limiting the number of plumbing fixtures that are on at once. If you experience poor water pressure when only using one plumbing fixture at a time, then you can assume there is a problem that needs to be fixed to restore proper water pressure. Here are five additional causes for low water pressure you should consider.

1. Outdated Fixtures

In some cases, low water pressure can be caused by fixtures that have become faulty over time. A build-up of mineral deposits, including rust, limestone or sediment, can obstruct the fixture and prevent water from flowing freely. This not only diminishes water pressure, but it can also impact the quality of the water that comes out as well. If you notice the water pressure is low in just one or two fixtures, then this may be the case.

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Test all your fixtures one at a time by turning them on and observing the pressure of the water coming out. Check to make sure any screens or aerators on your faucets are clean and unobstructed. If a screen or aerator is clogged, then you may only need to replace that piece to fix the issue. If this piece is clear, it may be that the fixture itself is clogged. If so, you can clean it out or replace it on your own.

If you replace your whole fixture, make sure to purchase a new one that will fit correctly. For faucets, after taking your old one out, measure the distance between the two outer holes. A distance of six inches or more means you need a wide-spread faucet. This faucet type requires you to manually connect the two valves to the mixing tee.

A distance of just four inches means you need a mini wide-spread or a center-spread faucet. This faucet type is already combined into a single unit encompassing all parts. You can tell the difference between a mini wide-spread and a center-spread faucet just by looking on top of your sink. A mini wide-spread faucet looks like three separate pieces, while a center-spread looks like all one piece. When you work on replacing a fixture, be sure to shut off the water supply.

2. Pressure Regulators

In some cases, a faulty pressure regulator may be the cause of low water pressure. It can also cause water pressure to be too high. If you find that there is little to no middle ground between low and high water pressure when turning on a faucet in your house, then this is a sign you are likely dealing with a failing water pressure regulator.

Not all homes are equipped with a pressure regulator, but if yours is, you will probably find this bell-shaped device below your home's front hose connection. Once the manufacturer sets the pressure regulator — typically to around 45 to 60 psi — it should not need adjusting. However, your pressure regulator can be adjusted by turning the screw at its tip. Gradually turn the screw clockwise to tighten it or counterclockwise to loosen it. Tightening the screw should cause your water pressure to increase, and loosening the screw should cause your water pressure to decrease.

If your water pressure was well-regulated before but is now too high, too low or both, then your pressure regulator may need to be fixed or replaced rather than simply adjusted. Pressure regulators can go bad, and when this happens, you should not try to fix or replace it yourself, as this can make problems worse. In this case, you are better off to rely on a licensed plumber to evaluate the situation and either repair your current pressure regulator or install a new one.

3. Water Valves

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Two main shut-off valves control the water flow in your home — one on or in your home and one at the meter. If one of these valves is partially or fully turned off for some reason, it can cause your water pressure to decrease greatly. This might happen when the water is temporarily shut off and then turned back on again — a valve could accidentally be left partially closed rather than opened back up all the way. If you think a closed or partially closed valve may be the cause for your low water pressure, check both main valves to make sure they are fully open.

To check the valve at your water meter, go to your water meter, which can be located either inside or outside of your home, and look inside the box. Many water utility companies install water meters near the edge of your property close to the street. If you live in an area that experiences harsh winters, your meter may be located indoors, probably in the basement, for protection. Sometimes, only city employees have full access to your meter, though you can still observe whether the valve is completely in the on or open position.

To check the home valve, look near your home's hose bib. Though this main shut-off is typically located on the exterior of your home, it can sometimes be in a utility room or basement. Shut-off valves are usually either ball or gate valves. Ball valves have a clear open and closed position, whereas gate valves need to be turned like a screw and may require several turns to fully open or close the water flow. If a valve appears to be broken, contact a professional who can see if the valve needs to be replaced.

4. Clogged Water Pipes

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Another potential cause of low water pressure is clogged pipes. One indication that clogged pipes may be the issue is if, when you first turn on a faucet, water sprays out at a normal pressure, but then it immediately begins to flow with noticeably less pressure. Pipes can become clogged over time as mineral deposits, rust or other debris build up on the insides of the pipes and restrict the flow of water. This is especially an issue with galvanized pipes. Galvanized steel is no longer the material of choice for new pipes for this reason. However, it used to be a very common material and is still found in many homes.

If you are not sure what the pipes in your home are made out of, find a pipe and use a nickel to scratch the surface so you can see the original color of the material. If the pipe's surface looks like a penny, then it is most likely made of copper, a very common piping material. Plastic pipes are also fairly common. These are usually black and are easy to identify by the visible clamps. The surface of galvanized steel pipes will look steel-gray in color.

While you can see what your pipes are made out of, this is where your investigation should end. Unlike some of the other problems that can cause decreased water pressure, you cannot check this one yourself. If you suspect your pipes may be clogged, call in a licensed plumber to take a look and determine whether the pipes need to be cleaned out or replaced. If so, the plumber should take care of this. You should not attempt to work on pipes on your own. Attempting to clean out clogged pipes when you do not have the expertise necessary is not only difficult, but it can also be dangerous — for instance, you could end up inadvertently contaminating your drinking water supply.

5. Corroded Plumbing

It's one thing if you only have a section of piping that needs to be unclogged or replaced, but in some situations, a home's entire system of piping can become corroded and may need to be completely replaced. Galvanized steel pipes have an average lifespan of 20 to 50 years. Materials like brass, copper and iron can last much longer, but even these pipes will need to replaced most likely somewhere between 40 and 100 years. If you live in an older house, your plumbing may have been there for many decades and has become severely corroded.

Replacing all the plumbing in your house is a large undertaking and is costly, but the results are worth the effort. When putting new plumbing in, you can choose a durable material so you most likely will not have to worry about replacing the piping ever again in your lifetime. Of course, this is a job for the professionals. Make sure you hire a licensed plumber to re-pipe your home.

Another thing to check is whether you need to enlarge branch lines. If you have added any new plumbing fixtures in your home, then the old branch lines may be too small. So, even though corrosion is not an issue in this case, you could still experience the same effect on your water pressure. The narrow interior of the line restricts the amount of water that can flow through.

Consult a Professional

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Many of the issues discussed above and more should be fixed by a professional. When it comes to plumbing, you do not want to neglect a problem or make the issue worse by trying to fix it yourself. When you encounter plumbing problems of any kind or when you want to check on your plumbing to ensure it is well-maintained, call Mr. Rooter Plumbing of Greater Syracuse at (315) 472-1203.

We offer comprehensive residential, commercial and emergency plumbing services to take care of any issues you experience, including those that reduce water pressure in your home. When you call one of our plumbers in to take care of a problem, you can also take advantage of a complimentary plumbing checkup to diagnose any other potential problems with your plumbing.

Our service is unmatched within the plumbing industry. We understand that dealing with plumbing problems can be stressful, but we can take the stress right out of it. We will schedule service as quickly as possible and provide you with a flat-rate upfront so you can rest easy that, no matter how long the job takes to complete, your cost will not change. Our plumbers' priority is getting the job done well, whatever it takes. You can also expect our plumbers to be courteous and treat your home with great care.

Contact us today to learn more about how we can help you enjoy great water pressure throughout your home!