5 Reasons Your Sprinkler Water Pressure Is So Low 

When your sprinkler water pressure is low, you’ll want to get to the root cause right away. Your lawn and garden need more hydration than what the reduced pressure provides. What has caused your sprinkler water pressure to decrease?

Here are 6 reasons your sprinkler water pressure is so low:

  • More people using the municipal water supply
  • Water line obstructions
  • Broken water line
  • Dirty sprinkler head
  • Closed valves

This guide to low sprinkler water pressure will examine the above 5 causes in much more detail. We’ll also recommend some fixes so you can improve your sprinkler water pressure and get back to tending to your lawn!

Identifying Sprinkler Water Pressure Issues: 5 Reasons for a Low Flow

More People Using the Municipal Water Supply

Before you begin tinkering with sprinkler heads or valves, it’s best to start with the easiest potential solution for your sprinkler water pressure troubles.

It could be that the municipal water supply is strained, and thus that’s why your sprinklers aren’t operating at full pressure.

Are a lot more people working from home in your neighborhood these days? You’re all pulling from the same source of water. If you and your neighbors try to use municipal water all at once, then the water pressure can’t be sustained for everyone.

Another situation could be that your neighborhood doesn’t have water usage rules. This might not be such a big deal in the autumn and winter, but as soon as the days start getting longer and the temperatures warmer, there is again a strain on the municipal water supply.

If you notice that your issues with sprinkler water pressure are most frequent in the summer, then you might have your culprit. 

Everyone wants water in the summertime, whether to water their dry grass or fill their pools. 

Some neighborhoods might not have enough municipal water for everyone, so the supply is severely strained. As a result, your sprinkler water pressure can plummet. 

So what do you do if you assume the problem is with your neighborhood’s water supply? It’s not like you have control over how much water the municipality allows to flow through your neighborhood, after all. 

That’s true, you don’t, but the municipality does. Get in touch with your water supply company. The company might not even know that there’s an issue afoot, which would make fixing it impossible. 

Once they’re aware, the water supply company might elect to begin implementing water usage restrictions, especially in the summertime. 

Before you know it, your sprinkler water pressure will be consistent again. 

If the water supply company already has a water usage limit in place but it’s not making enough of a difference, then you’ll have to get crafty in when you turn on your sprinklers. 

You can either do so very early in the morning or later at night. During these two periods, fewer of your neighbors are awake and active, so you’ll have more of the municipal water supply to yourself. 

Water Line Obstructions

You don’t have X-ray vision and thus can’t determine what’s happening underneath your home deep in the ground, but something could be wrong with the water line. 

That’s likelier if your municipal water supply water flow is not being impacted yet your sprinklers still don’t have much water pressure.

Do you know roughly where your water line is located on your property? If not, then you need to ascertain this information first. 

How do you do that? Look for the water meter that’s attached to or adjacent to your home and then continue outward until you see a colorful knob or handle. The knob or handle can be green or red. 

This is the water shut-off valve, which we’ll get to later. For now, all you need to know is that your water lines are likely in the vicinity. 

Once you’re surer of where the water lines are, look for shrubs or trees growing near the water lines. 

If you have well-grown greenery that’s been around for many years, then it could be that the roots of the tree and/or shrub have expanded far enough underground that they’ve choked off the water line.

The weight of the tree or shrubs could have caused the soil to become hardened and compressed. The water line underneath is compacted by the damage and thus can’t provide a consistent water pressure.

If not that, then the squeezing of the roots might have squashed the water line. The line could be squeezed or crimped closed, which prevents water from getting through efficiently as well.

If you have an issue with your greenery impacting the water line, then it won’t just be your sprinkler that lacks water pressure. The fixtures in your house will also probably be negatively affected. 

What if you don’t see any trees or shrubs nearby? Well, do you or another family member often park your vehicles near the water line (probably without knowing it)?

The long-term weight and pressure of a car or truck on the ground over the water line can absolutely create the same kinds of pressure on the water line that a tree or shrub could. 

The same can also happen if the area where the water line is frequently receives a lot of vehicular traffic, such as if you live on a busy road. 

You won’t be able to fix a water line obstruction yourself. You can’t even confirm it yourself since you don’t have the tools or the means to access the water line. 

Instead, you should contact your water supply company or a plumber. 

Once the plumber treats the water line obstruction, your sprinkler water pressure should be as strong as ever. That goes for the water pressure in your home as well!

Broken Water Line or Sprinkler Line

If the water line hasn’t been squashed all this time, that doesn’t mean it’s not potentially damaged or even broken.

Long-term pressure can cause the water line to splinter or crack. When this happens, water now actively leaks out of the line, never reaching your home. 

Again, this is a problem that affects water pressure throughout the whole house. You’ll notice lower water pressure not only when you turn on your sprinkler, but potentially when you shower, use your kitchen sink, or when you run the dishwasher.

It could also be that your sprinkler line has been destroyed.

If you recently got electricity lines, gas pipes, or cable lines installed around your property, that could have potentially damaged the sprinkler line. 

After all, to install the above lines or pipes, a technician had to dig holes in the yard. Either they did or you did, but someone did.

If you recently renovated your yard, then once again, your sprinkler line could have been struck in the process. Now it’s sputtering and you barely get any water from the sprinkler system. 

You’ll have to unearth the sprinkler lines to check their condition. If the lines are in inoperable shape, then you’ll have to get them replaced. You can do this yourself or hire a professional to take care of the job. 

As for a broken or splintered water line, that’s not for you to repair. Again, defer to a plumber or a technician to get your water line in working order again. 

Dirty Sprinkler Head

Here’s another fix that’s rather easy but can be effective, especially if you can rule out issues with the sprinkler line, the water line, or your municipal water supply.

Go outside and inspect all the sprinkler heads in the system. If they’re dirty, then your water pressure will suffer.

Perhaps you leave the sprinkler system out all year, even if you only really use it in the spring and summer. 

It could be that during all that inactivity, grass had time to grow around the sprinkler head. You might not have even noticed it. You only realized that something was wrong when you turned your sprinkler on, and that one head barely sputtered out any water.

Even if grass isn’t growing directly on a sprinkler head, that doesn’t mean that grass couldn’t be the issue. 

For example, if it’s been months since you’ve last mowed your lawn (which is normal in that transitionary period between late winter and early spring), then the grass could have grown so tall that it’s blocked the sprinkler head holes.

Take the time to clean out your yard. Mow the lawn and remove any weeds growing in the vicinity. That could be all it takes for your sprinkler system to work with the appropriate water pressure.

In other instances, it might not be grass at all that’s reduced the flow of the sprinkler system. Perhaps the sprinkler heads are dirty.

All it takes is a crack or two in your irrigation line and dirt can get into the sprinkler heads, usually where you can’t easily see it. 

At that point, you can clean the exterior of the sprinkler heads, but your best bet is to flush the line with water.

Make this a regular enough habit and you shouldn’t have water pressure fluctuations affecting only some of the sprinkler heads. 

Closed Valves

Hmm. So far, none of these issues have been why your sprinkler water pressure is so low. Well, don’t give up yet, because we have another common problem to go over next.

That is, one or more of the valves associated with the sprinkler system isn’t fully open when it’s supposed to be.

Let’s begin by talking about the main water valve. 

The main water valve is also known as the shut-off valve, as you’d turn this valve to either allow a full water supply to your home or to cut off that water supply. 

We touched on the shut-off valve earlier, as you’ll recall.

The city will install this valve as well as several others. Water supply valves feature either a ball valve or gate valve design. Ball valves are common in homes with copper or plastic main water pipes. 

Since the main water valve can turn off all the water to your home, if it’s left partially open, then your home will receive some water, but intermittently. This can explain why your sprinkler system water pressure is low.

You should know where your main water valve is and how it works so that if you ever have a flooding emergency, you could quickly turn the water off. 

Most water supply valves are either outside on a wall near a utility area (as we mentioned) or down your basement.

If yours is a ball valve, then adjust it with a quarter turn, rotating the valve clockwise. The valve should be pointed towards the pipe at a precise right angle.

As for gate valves, if you haven’t touched yours in a long time, then it will feel like the valve won’t want to budge. That’s an unfortunate side effect of gate valves, that they don’t rotate easily if they’ve been idle for years.

Try your best to move the valve into an open position. 

The other valve you should check belongs to the backflow preventer.

This device safeguards your water from backflow and the pollution and contamination that often comes with it. Your home will have more potable water for cooking, bathing, and drinking. 

A backflow preventer can restrict the travel of water in certain directions. Thus, while the water levels in your home could be fine if the backflow preventer valve is not all the way open, your sprinkler may barely spit out water.

Most backflow preventers feature both a vertical and horizontal pipe. You’ll have to open a valve for each pipe or the problem with the sprinkler water pressure will persist. 

Start by turning the valve on the horizontal pipe, then the vertical pipe.  

Final Thoughts

If your sprinkler system has low water pressure, it’s usually due to one or more of the reasons we discussed today. Some of these causes don’t require complicated fixes or expensive repairs, which is great for you.

Other problems with low sprinkler water pressure will demand that you call out a plumber or technician to get your water lines in better condition or to repair broken pipes. Don’t wait too long, as cracked pipes could lead to catastrophic water damage.

In the future, be sure to maintain your sprinkler lines to keep them working their best! 



Geoff Southworth is the creator of RealEstateInfoGuide.com, the site that helps new homeowners, investors, and homeowners-to-be successfully navigate the complex world of property ownership. Geoff is a real estate investor of 8 years has had experience as a manager of a debt-free, private real estate equity fund, as well as a Registered Nurse in Emergency Trauma and Cardiac Cath Lab Care. As a result, he has developed a unique “people first, business second” approach to real estate.

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