Sumo Gardener

How the Wrong Garden Water Pressure Could Hurt Your Garden

Issues with the water pressure are most noticeable when they impact tasks like showering or washing dishes. Few of us tend to worry about water pressure outside of the house like garden water pressure.

Read on and learn how inconsistent garden water pressure can impact your garden. 


How the Wrong Garden Water Pressure Could Hurt Your Garden
How the Wrong Garden Water Pressure Could Hurt Your Garden

If there are any pressure concerns, it’s a problem for another day. However, avid gardeners are the exception. We understand the need for a consistent, nurturing water supply.

Low water pressure can turn gardening into a time-consuming process for all the wrong reasons. If watering by hand, finding a garden hose with the right water pressure means significant time saved.

But that’s not the only issue. High water pressure can damage your plumbing systems. This means your irrigation system, sprinklers and outdoor taps could all be at risk.

The average American home’s water pressure sits at 50 pounds per square inch (psi). Fifty psi is seen as a safe and controlled level. Anything below 40 psi is viewed as low pressure, while 70 psi or above is too high. 

Water pressure is something that can fluctuate wildly from home to home. Individual circumstances mean your pressure could be sitting at 40 psi, while your neighbour has 65 psi.

Factors such as your water source, internal plumbing and even the location of your house can impact water flow quality. And if that has left you with water pressure that’s too high or too low, it needs to be rectified.

Being aware of the risks, and knowing the right solutions, will help you avoid any major problems.

Importance of Garden Water Pressure

Importance of Garden Water Pressure

The health of your garden could be at risk if your water pressure is not right. In particular, the first few weeks after planting or transplanting is when vegetable gardens and plants are most susceptible to adverse effects from water shortages

Meanwhile, lawns require a decent wetting depth of between 4-6 inches to truly benefit the root system. Anything less could lead to shallow root systems and greater susceptibility to stress.

Lawn growth can easily be impacted by low water pressure. For example, pop up sprinkler systems and oscillating sprinklers may not activate if the supply pressure is too low.

If you happen to water the garden at night, or set timers during the day while you’re at work, you may not witness water supply issues until it’s too late.

Additionally, too much water pressure will have a negative impact on sprinklers. However, instead of providing a consistent water supply, water will be released as a mist.

It will evaporate far more quickly in hot conditions, meaning your garden is losing vital hydration. High water pressure could also damage your irrigation system. If plumbing connections and hoses are placed under too much stress they will break. 

Hidden leaks around the home can easily damage your belongings or the foundations. Over saturated soil will shift, causing gradual movement in walls and garden paths. 

Precision drip irrigation systems require a consistent water flow rate. It’s likely that you have set the system up with a specific goal in mind, especially if you have a vegetable garden.

This is where various vegetables require different amounts of water. Any unexpected changes from fluctuating water pressure will impact quality. 

Therefore, you want to know exactly what your home’s flow rate is, and the water pressure provided by your garden taps.

How to Check Water Pressure

How to Check Water Pressure

If your garden hose is releasing a trickle, or if your sprinklers are inconsistently spraying, it’s easy to check your home’s water pressure. There are several water pressure gauges available for personal use from local hardware stores. They are easy to use and do not require any professional installation. 

The two main options on offer are the:

“Lazy Hand” Water Test Gauge - Easily attached to any hose bibb, you leave the Lazy Hand water test gauge on overnight - or for a few days - to receive the best possible results. It will show you the highest pressure reached so you can be aware of any serious spikes. 

Standard Water Test Gauge - This requires a touch more attention as you need to observe the fluctuations consistently. You can view in real-time the water pressure of your outside garden taps/fittings.

These water pressure gauges will clearly show your water pressure, indicating whether action needs to be taken, or not. If the water pressure sits within the ideal range of 45-60 psi, you can sit back and relax.

Anything lower or higher, then it is best to look into the matter yourself, or contact a local plumber for further solutions. 

The Main Sources of Household Water

Much of America’s freshwater supply is collected in reservoirs or dams. Once treated, potable water is transported through a distribution system, ultimately ending up in millions of homes.

In many cases these water sources can be hundreds of miles away. Several pumping stations may be located in your distribution system, or none at all. It depends on where you live.

Distribution systems are also responsible for creating water pressure. This is commonly achieved by pumping water to the top of a high water tower/tank and letting it flow downwards.

The force created by the drop builds enough pressure to flow through municipal plumbing systems. The pressure level is far higher than what is required inside a home.

Therefore, once it hits your mains water meter, it is reduced via a valve. However, in many older homes, these can deliver an inconsistent pressure and are not always a uniform or regulated pressure.

Main Sources of Household Water

Meanwhile, other water supplies for the garden can also come into play. Harvested rainwater from gravity or rainwater tanks is quite common. Newer tanks are more likely to be installed with pressure sensitive pumps or inline pump controllers. Older ones may rely purely on gravity fed water.

Curious to know just how much water you’re receiving per day? A simple household water flow rate calculator test includes filling up a bucket to discover how many gallons of water flow through your pipes per minute (gallons per minute/gpm).

You can discover this by recording how long it takes to fill a one gallon bucket with the tap opened at maximum flow rate. Your gpm flow rate will be 60 divided by the recorded time.

For example, if the bucket is filled in 10 seconds, 60 divided by 10 equals six gallons per minute. If the bucket is larger - say 3 gallons - then 180 is divided by the total time recorded. 

Ideally, it should fall somewhere between 6-12 gallons per minute. Your answer may not be 100% accurate, but will be reliable for future reference.

How Water Pressure Changes in the Garden

Residential irrigation systems consist of five main parts: the water meter, backflow preventer, control valves, mainline and lateral lines. Throughout each part of the system there will be some pressure lost. 

According to the 5-4-3-2-1 rule of thumb you can expect a total loss of 15 psi from the water meter to a sprinkler head. This may vary depending on the design of your irrigation system and initial water pressure supply.

Irrigation rotors typically operate between 25-65 psi, while drip systems require 15-30 psi. In terms of your drip system, it is easy to control water pressure and flow rates with the line size.

Smaller lines will slow down the flow rate, which is perfect for tailored watering solutions. A ½ inch line will restrict the flow to around ½-2 gpm, while a larger 1 inch drip line allows for between 4-8 gpm.

Meanwhile, standard sprinkler spray heads sit right in the middle with an optimum pressure of 30 psi - a figure that’s arguably the most versatile. Knowledge of the sprinkler’s water requirements will also assist in coordinating your watering schedule.

A sprinkler system with three heads that each use three gallons of water per minute will not overload your supply. However, if you were to use all three while someone was showering inside, there would be a noticeable dip in pressure for all.

How Water Pressure Changes in the Garden

Influences on Garden Water Pressure

Water flow and water pressure can be affected by broken pipes, clogged drains, improper pipe sizes and more. Much of the time there is a solution, however, uncovering the cause is always the trickiest part.

Damaged pipes are rarely hiding in plain sight. It is likely that a leaking pipe - or burst pipe - is not instantly identifiable. You will see the telltale signs of the leak with your reduced water pressure, yet the cause could literally be buried underneath your home. 

Remain vigilant for damp spots inside the home and puddles in the garden. Both are signs of a leaking pipe and the reason why your taps are not receiving the full water supply they should be.

Any issues surrounding damaged or leaking pipes should be repaired by a licensed plumber. Clogged drains can prove to be a handful. Invasive tree roots are likely to compound any damage by both blocking pipes but also cracking them, causing leaks.

Blockages such as this are likely to cause water pressure issues throughout the home. More centralized concerns include debris inside the pipework your garden tap is connected to.

For example, debris, rust and other sediment can build up around valves and openings. So there could be a blockage isolated right behind the faucet impacting one specific tap.

Other issues include plumbing that is just too small for your requirements. Pipes that are ¾” are ideal for water supply. They are large enough to allow a strong flow rate that delivers water pressure in the 45-60 psi range.

How to Resolve Garden Water Pressure Issues

How to Resolve Garden Water Pressure Issues

Fortunately, low or high water pressure doesn’t necessarily require emergency plumbing. There are several proactive and reactive maintenance strategies to use around your property.

One of the most common solutions is a pressure reducing valve, or PRV. PRVs are regularly used by plumbers to reduce water pressure to controlled and consistent levels. Typically they are set to 45 psi. They are required by code in many major cities to ensure 80 psi is never exceeded in a home.

Alternatively, you may need to increase the water pressure. Water pressure pumps will deliver a more consistent water pressure for homes with low flow rates. It is also possible to control your water pressure directly, providing a tailored approach to gardening and irrigation. 

If your water issues are related to hoses and irrigation systems there are several steps you can take for improvement.

Simply swapping your hoses from ⅝” to ¾” will allow for a larger flow rate, sometimes up to 60% more. The increased flow rate means you also have increased pressure.

This is incredibly beneficial for any sprinkler or irrigation systems running uphill. It also means you can consistently water your garden both near and far from your outdoor tap without drastically losing pressure.

Meanwhile, the solution could be parts related. Also referred to as a hose bib, spigot or silcock, your water flow may be bottle-necking at the outdoor faucet if it is not a full ¾”. Replacing the faucet will expand your water flow capabilities.

Likewise, there could be a bottleneck at splitters. Splitters are used to divert the water supply in two directions. Some splitters contain small ball valves that restrict the flow of water. Investing in full flow splitters ensures your water does not have to travel long distances and lose pressure for sprinklers.

Wrapping Up Our Garden Water Pressure Guide

Your garden will likely require a tailored irrigation system and watering schedule. It all depends on the climate and the unique combination of vegetables, fruits and plants you have.

However, the importance of acting early with water pressure issues cannot be understated. Regardless of the make-up of your garden, if you feel like your water pressure is having a negative impact it’s best to act fast. 

You don’t have to contact a local plumber or handyman - although that’s often an easy solution for long term success. But by taking advantage of water pressure gauges you can identify any issues on your own.

Understanding what’s wrong with your garden’s water pressure means you can be proactive. Pressure reducing valves or water pumps are non-invasive solutions that can be added to any irrigation system for a consistent, nurturing watering cycle.

There you have it, everything you need to know about garden water pressure and how to important it is for your garden. 

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About the Author Pat Moreno

Pat is our gardening tool expert here at Sumo Gardener. Working for many years as a private and commercial landscaper, Pat has used almost every type of gardening tool there is. Along with a vast knowledge for types of plants and putting together an amazing looking and maintainable garden, Pat developed a passion for gardening tools as he found that using the right tools vastly improved the ease and outcome of any landscaping job he undertook. When spending hours, days or years using a particular tool, you want to make sure you’ve got the best one for the job, and Pat is the right guy to guide us to the best gardening tools.

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