Drip Irrigation: Do You Really Need A Pressure Regulator?
Drip irrigation is one of the most efficient and cost-effective irrigation systems available to hobby and commercial growers alike.
But the setup and design can be confusing, and it’s tempting to rule out all unnecessary components to help cut costs.
Are pressure regulators an optional part of a drip irrigation system?
In short – no, pressure regulators are not optional in a drip irrigation system. Pressure regulators help prevent leaks, emitter blowouts, premature system damage, and irregular water application. If you want your irrigation system working fully, you need a pressure regulator.
But wait, there’s more.
Before we discuss the importance of pressure regulators in your irrigation system, let’s cover the basics of drip irrigation.
Why to Choose Drip Irrigation over Sprinklers or Hoses
If you’re just starting to garden or if you’re looking to improve the health and quality of your plants, drip irrigation is worth considering. The benefits of drip irrigation are plenty!
- Drip irrigators maintain a more stable balance of moisture and oxygen in your soil.
- Drip irrigators are more than 90% efficient (20%-40% more efficient than sprinklers), which makes them exempt from drought restrictions in many areas (check with your local utility company first).
- Drip irrigators can easily water narrow, sloped, or hard-to-reach areas in your garden.
- You can install a drip system yourself and change your set-up as your plants’ needs change (source).
Overall, while a drip irrigation system may seem intimidating or highly technical, it can save you water, increase your yields, and save you money in the long run.
How Drip Irrigation Works
Drip irrigation is a system of tubes and emitters that delivers water exactly where it is needed.
If you are familiar with soaker hoses, hoses with a series of holes designed to distribute water along their length, then you may be thinking that drip irrigators are essentially the same thing. While they share a few similarities, drip irrigation systems are much more sophisticated than soaker hoses.
Unlike soaker hoses, drip irrigators’ emitters release a slow, steady, precisely controlled amount of water to an exact location. Each emitter is rated for a specific flow per hour, and each system is designed to deliver enough water to each emitter to attain that hourly output.
Furthermore, unlike soaker hoses, drip irrigators are often anchored in a location semi-permanently. Many gardeners run their drip irrigators alongside rows of vegetables, for example, but move them as the growing season progresses.
Drip irrigation does the following:
- Reduces or eliminates runoff
- Reduces evaporation
- Reduces wind drift
- Reduces nutrient leaching
The overall output of a system is a complicated formula that takes the number of emitters, output per hour, and the length of tubing into account, and determines how much pressure it will take to keep the system running as needed.
This is where we introduce a pressure regulator.
How a Pressure Regulator Works
In scientific terms, pressure is measured as the amount of force per unit of area. Water pressure (like tire pressure) is measured in pounds per square inch (PSI). A pressure regulator regulates the PSI of the water flow in the drip irrigation system.
For most households, the water pressure is above 30 PSI and most drip irrigation systems operate between 15 PSI and 35 PSI. A drip irrigation system must run at a lower PSI than what comes into the spigot. In general, a drip irrigation system should be regulated down at least 10-15 PSI from the incoming water source (source).
There are some tricks to get around low incoming pressure, but in most cases, you want the PSI coming into the spigot to be higher than the required PSI of the system. This allows you to add on to the system, and it also ensures water will reach out to the farthest emitters and supply adequate water to each plant.
In order to maintain constant pressure within the system, the PSI must be throttled to match the capacity of the hoses and emitters without causing a blowout.
Pressure regulators not only maintain a constant PSI, but they also mitigate surges and dips from the incoming water source.
This is how a pressure regulator controls the incoming and outgoing flow of water:
- Water passes from the source to the inlet of the pressure regulator
- Water flows around a fixed seat and into the throttling system
- Water flows through the t-stem and presses up against a diaphragm mounted on a spring
- The spring adjusts according to the incoming PSI; the higher the incoming PSI, the more compressed the spring, and the more restricted the outgoing flow of water
- The outgoing water is a constant PSI regulated by the balancing act between the spring and diaphragm
Even if the water source has a PSI that matches the required PSI for your drip irrigation system, you should still use a pressure regulator to manage surges and prevent damage to your system.
How to Choose the Right Pressure Regulator for a Drip Irrigation System
Ultimately, the right pressure regulator for you is a matter of budget and personal preference. However, there are several things to consider before you pull out your wallet.
Regulators vs. Reducers
First, let’s clarify the difference between a pressure regulator and a pressure reducer. Both are available for drip irrigation systems, but they don’t have the same function.
A pressure regulator costs a bit more, but maintains a stable level of water pressure, even when there are surges or losses of pressure. Pressure regulators are also better at adapting to the varying pressure needs of drip systems that are installed on sloped ground.
A pressure reducer simply reduces the pressure from your water source to the level you specify, but won’t adapt to surges or losses in pressure.
A pressure regulator will mitigate problems for the entire drip irrigation system, but pressure reducers can be installed at different valve points along your system. For example, if your garden contains plants that have different watering needs, a pressure reducer in the right place can keep your system from over or underwatering your plants (source).
Depending on your needs, you may wish to buy a pressure regulator and one or more pressure reducers. However, for most backyard gardeners, a pressure regulator alone will be enough.
Pressure regulators for drip irrigation systems will have a max inlet pressure and a set output pressure.
Inlet pressure refers to the water flowing into the regulator from the water source. Output pressure refers to the pressure of the water coming out of the regulator.
If the pressure from your water source is higher than the max inlet pressure of your regulator, the best-case scenario is that your regulator won’t function properly. The worst-case scenario is that it will break altogether.
Before you buy a regulator, make sure that you check the max inlet pressure listed on the manufacturer’s label. The max inlet pressure will likely be much higher than the pressure from your water source, but it’s wise to check anyway.
Adjustable vs. Preset
Another consideration is whether you want an adjustable pressure regulator or a preset one.
Adjustable pressure regulators do exactly what their name suggests: they let you adjust the PSI of the water flowing into your irrigation system. For example, if you wanted the water pressure to be 25 PSI, but later learned that was too high, you could simply lower the PSI on your regulator without needing to buy a new one.
The PSI on preset pressure regulators, on the other hand, are determined by the manufacturer. For example, if you wanted the water pressure in your system to be 25 PSI, you would need to buy a 25-PSI regulator. To adjust the pressure, you would need to remove one regulator and install one with a different pre-determined PSI (source).
Each type of regulator comes with advantages and disadvantages. Adjustable pressure regulators cost more upfront but offer much more flexibility. Preset regulators can’t be adjusted but lower the risk of “user error”; a gardener can’t accidentally set the pressure too high or too low.
Pressure regulators come in heavy-duty brass or plastic. While there is no difference in function between the two, there is a significant difference in price. Plastic regulators often cost significantly less than brass ones, sometimes as much as 75% less (source).
Drip Tape vs. Drip Tubing
Your choice of regulator also depends on whether you use drip tape or drip tubing in your irrigation system.
Drip tubing is sturdier and can handle higher pressure levels, sometimes up to 30 PSI.
Drip tape, on the other hand, is much thinner than tubing. 10 PSI is ideal for drip tape; if the water pressure exceeds 15 PSI, drip tape is likely to burst.
If you plan to use drip tape in your irrigation system, make sure to get a preset pressure regulator that will maintain 10 PSI. If you use drip tubing, a 25 or 30 PSI regulator should work well, as long as 30 PSI is lower than the unregulated pressure from your water source (source).
Buying and Installing Your Pressure Regulator
Several factors influence the cost of a pressure regulator, including vendor, manufacturer, and regulator type.
If you’re just beginning your endeavor into drip irrigation, you may actually prefer to buy a drip irrigation kit. Kits often include the tubing, stakes, and emitters as well as a pressure regulator calibrated for that system. Depending on how much tubing you need, a kit may cost between $30 and $60.
You can buy a basic, plastic, preset regulator for as little as $10 or as much as $40, depending on the vendor and manufacturer.
Again, if pressure regulators and drip irrigation systems seem highly technical, do not be intimidated! Pressure regulators are very easy to install.
You will most likely be able to install the pressure regulator by screwing it directly onto your garden hose and tubing. Follow the manufacturer’s instructions closely to avoid accidental damage to your equipment.
Drip irrigation systems are well worth the time and money you’ll invest setting them up. Regardless of the size of your garden, a drip system will prevent water loss while still delivering just the right amount to your plants. With the right pressure regulator, you can maintain your drip system and enjoy the fruits of your labor for years to come!
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