Welcome to the Pressure Regulator Buying Guide! If you’ve made it this far, you’re probably on the right track. In this guide you will learn about pressure regulators; what they do, who needs them, how they work, and what information you’ll need to determine the best device for your system. 

If you would like a quick overview of what you need to know about your system to select a unit - check out our Pressure Regulator Flow Chart.

For a more comprehensive overview, continue reading!

What does a pressure regulator do?

The water pressure regulator maintains the pressure within the system and protects against spikes or sudden drops in pressure from the water source. This device ensures the pressure within the system will stay consistent, thus resulting in optimal performance from the emitting devices.

Please note, various watering devices may specify they are “pressure compensating” however, this is different than pressure regulation. Compensation refers to an emitter consistently disbursing the pre-set flow rate, regardless of small pressure changes, however, pressure compensating emitting devices will not regulate the system pressure. 

Who needs a pressure regulator?

Most if not all, pressurized irrigation systems will require a pressure regulator. An exception to this would be if you are using a gravity system with very low pressure, or very low flow. Pressure regulators do require sufficient flow to regulate the pressure and at least a 5 - 15 PSI differential between inlet pressure and regulating pressure.

How does a pressure regulator work? 

Water flows through the inlet, around the seat and through the t-stem. Water pressure acting on the diaphragm forces the spring to compress, pushing the t-stem toward the seat. The closing of the area between the seat and the t-stem reduces the water pressure on the diaphragm. The balance between the force on the diaphragm and spring resistance establishes the outlet pressure.

Irrigation pressure regulators need outflow and back pressure to regulate the pressure within your irrigation system. With no water flowing through the regulator, the inlet and outlet pressures will measure the same. To verify the pressure maintained in your system, you will need to place a pressure gauge at the end of one of the zones, turn the zone on, let it pressurize and once the lines have filled and emitters begin to flow then take the reading. This will reflect the working pressure within your system. To learn more on testing pressure regulators, see this short video: How to Test a Pressure Regulator. 

Because of this, a certain amount of pressure (PSI) and flow (GPH/GPM) is required for a pressure regulator to operate. 

What factors should be considered when selecting a pressure regulator?

1. Flow rate of the system - Not just the water source

In order for a pressure regulator to operate correctly, a certain flow rate must be met. Not just at the inlet of the regulator, but through the outlet as well. This means your system must meet a certain amount of flow. 

If you need to determine the flow rate of your water source, here is our flow rate calculator. 

To determine the flow rate of your system, you will want to add up the number of emitters and multiply by the emitter flow rate. For instance, if you have 100 emitters with a flow rate of .5 GPH, (100 emitters x .5 GPH each = 50 GPH). You will want to take into consideration the flow rate of your system is 50 GPH. 

To convert from gallons per hour (GPH) to minutes (GPM), simply divide by 60 (minutes). In this example, 50 GPH/ 60 minutes = .833 GPM.

• Low flow is typically 6 GPH (.1 GPM) to 420 GPH (7 GPM)
• Medium flow is normally 120 GPH (2 GPM) up to 1200 GPH (20 GPM)
• High flow is 600 GPH (10 GPM) up to 1920 GPH (32 GPM) 
• Ultra High flow is 1200 GPH (20 GPM) to 6000 GPH (100 GPM)

2. The pressure (PSI) of the water source and PSI requirements of the emitting devices

Checking the pressure of your water source can be done using a simple pressure gauge fitted with the hose thread adapter, here is a link to our selection of Pressure Gauges. Most pressure regulators require at least 5 PSI above the preset pressure in order to regulate the pressure. Meaning if you’re using a 20 PSI regulator, your water source must provide at least 25 PSI. 

3. The system configuration - Thread type and installation

Our pressure regulators are offered in a variety of thread types and sizes including pipe thread (NPT, FPT, MPT) and hose thread (FHT, MHT), in both female (F) and male ends (M), from ½” up to 3” connections. 

None of the standard pressure regulators we carry are rated for constant pressure. Meaning, that these must be installed after any timers or valves in order to ensure that the pressure is relieved during static (no flow) conditions. See the Senninger PRLV for downstream valve operation options.

When installing a head assembly in a hose bibb system, we recommend the following head assembly order of components: Timer (optional), Backflow Preventer, Filter, Pressure Regulator, 1/2" Swivel adapter or tubing adapter. For more information on head assemblies, check out our “Do I need a head assembly?” article. 

Here is a quick chart showing some of the Pressure Regulators we offer:

2-in-1 Pressure regulators:

In addition to regulating the pressure within the system, various manufacturers have also included an added filter element to help eliminate or reduce the need for additional system components. Various manufacturers (such as Aqualine and Hydro-rain) make 2-in-1 filter and pressure regulator combinations. These combination devices are great as they save money and space in your system assembly. 

Here is a quick chart:

Other regulators and pressure devices:

There are some system configurations where a pressure regulator is best installed at the valve. In this case, the Irritrol Omnireg Adjustable Pressure Regulator is a great item to use (please note this is only compatible with Irritrol Valves) directly on the valve. This device allows the user to precisely set and maintain the exact downstream pressure required for almost any application. It is adjustable from 5 PSI up to 100 PSI, by simply turning the easy-to-use dial to the desired setting.

Finally, the last device we will cover in this article are the pressure reducing valves. Pressure reducing valves are different than pressure regulators. One of the biggest differences with the reducers we carry is that they are able to withstand constant pressure, unlike pressure regulators.  

If you have any questions, comments, or feedback, don't hesitate to get in touch with Us. We read and reply to every message we receive and would love to assist with your questions and learn from your feedback.