Drip Irrigation FAQs

Do I need to install a separate valve for my customer’s drip irrigation system?
Every drip system needs a shut off valve, control valve, a pressure regulator, and a filter. Whether you will need a separate shut off valve for a drip system depends on if you are replacing an entire sprinkler system or adding drip to your customer’s current irrigation system. If your customer wants to replace their entire system, you can use the existing shut off valve and retrofit control valves for the new drip system. 

If you’re adding drip into a lawn sprinkler system, it’s recommended to have a separate shut off valve. In this process, create a separate zone with a control valve or pressure reducing valve and filtration unit at the start of the zone to keep this separate from the sprinkler zone valves. This is necessary because drip systems and sprinkler systems aren’t compatible; they operate at different pressures and run times.   

In either scenario, you can retrofit sprinklers by capping off spray heads around planter beds if they are placed after the pressure reducer and filter. Then driplines can be run from existing pipes.


Why do I need a pressure regulator with a drip irrigation system?
Most drip systems operate at a lower water pressure than standard irrigation systems use. According to Green Industry Pros Magazine, most manufacturers recommend a maximum of 40 PSI for drip systems. Check the flow rate and use a pressure meter to gauge customers’ pressure at the water source.

Using a pressure regulator, also called a pressure regulating valve, lowers pressure and keeps it consistent. Without this, the fittings can pop off, emitters can become distorted, and the system will not work effectively. 

There are three types of pressure regulators. Make sure you buy the correct regulator for your customer’s needs. The first is non-adjustable pressure regulators. These are best for small residential drip systems with fewer than three control valves. These non-adjustable pressure regulators have specific flow ranges and will not work if the flow is higher or lower than its specified range. They are normally made of plastic and have a pre-set outlet pressure. Install these after the control valve. If there’s more than one control valve, you’ll need a pressure regulator for each one. If a non-adjustable pressure regulator is installed before a control valve, the pressure regulator could have pressure surge, which can potentially damage the whole system. 

Adjustable pressure regulators are more flexible and accurate than non-adjustable regulators. These are typically brass or bronze and have a large screw to adjust outlet pressure. Like any regulator, ensure you buy the correct size for the job’s necessary flow rate specified by the manufacturer. You can install adjustable pressure regulators before or after the control valve. On larger drip systems with multiple control valves, the valves are often grouped together, and one adjustable pressure regulator is installed on the mainline before all the valves in a group to save money and time. Regulators require a pressure drop between the inlet and outlet of the regulator to operate effectively. If the pressure drop is less than required, the regulator will work less accurately, and pressure may substantially vary. 

Some irrigation manufacturers offer a drip control zone kit which provides all the components necessary for on/off control, filtration, and pressure regulation in a single package, making them simple to order and easy to install. Drip control zone kits are preassembled with a filter, valve, and pressure regulator for a complete control zone solution. These kits come in a variety of flow ranges and have different capabilities from small residential installations to commercial projects. 

Visit your local SiteOne branch or the irrigation section of our website today to make sure you have the right tools and parts for your next drip irrigation installation job.