Guide · Faucet head assembly
Drip pressure regulators: outlet PSI, flow range and static pressure
How to choose a drip pressure regulator by outlet pressure and flow range, why a gauge reads high with the line closed, and the ranges makers list.
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Short answer
Choose a drip pressure regulator by two numbers: an outlet pressure your drip parts are rated for, and a flow range that includes your system's total flow. Most standard regulators only regulate while water flows; with the line closed, the gauge can read inlet pressure. Then match its threads to the parts on either side.
Do I need one?
Faucet pressure is often higher than drip parts are rated for. DIG says most drip systems operate best between 20 and 50 psi, and names high pressure as the typical reason a drip system functions improperly.[1] Individual parts have their own, often narrower, ranges, so check the lowest maximum among your parts.
Senninger, a regulator maker, recommends regulators where pressure varies by 20%, noting that a 20% pressure change equals about a 10% flow change.[2]
What PSI should a drip regulator be?
Pick an outlet pressure inside the range of every part downstream. DIG's D54, for example, is preset to 25 PSI.[3] Rain Bird's PRF07530SX is rated at 30 psi.[4] Mister Landscaper says its 25 psi regulator is required when running drippers only, or a mix of drippers and micro-sprays, and suggests its 50 psi regulator for micro-sprays.[5] Those figures are for its own system.
Leave headroom at the inlet. Senninger recommends inlet pressure at least 5 psi higher than the regulator's expected outlet pressure.[2]
Flow range: the number people miss
Makers rate each regulator for a flow range, not just an outlet pressure. Keep your zone's total flow inside that range.
| Model | Outlet pressure | Flow range | Threads |
|---|---|---|---|
| Rain Bird RBY 3/4 in (PRF-075-RBY) | 30 psi | 0.20-5.0 gpm | Not stated on its page |
| Rain Bird RBY 1 in (PRF-100-RBY) | 40 psi | 3.0-15.0 gpm | Not stated on its page |
| DIG heavy-duty presets | 20, 25, 30, 35 or 40 PSI | 0.5-12 GPM | 3/4 in FNPT inlet; outlet by part |
| DIG D54 filter/regulator | 25 PSI preset | Up to 6 GPM | 3/4 in MNPT both ends |
| Senninger PRL | 6-40 psi presets | 0.5-8 GPM | 3/4 in F NPT or F hose inlet |
| Senninger PRLG | 10-40 psi presets | 0.5-7 GPM | 3/4 in F hose or F NPT inlet |
| DIG adjustable, white / red | 12-35 psi / 28-60 psi | 0.88-22 GPM | 3/4 in FNPT |
| Rain Bird PRF07530SX | 30 psi | Not listed on its store page | 3/4 in MPT |
Rain Bird lists its 3/4 in RBY unit at 30 psi for 0.20 to 5.0 gpm and its 1 in unit at 40 psi for 3.0 to 15.0 gpm.[6] DIG's heavy-duty presets handle 0.5 to 12 GPM in 20, 25, 30, 35 and 40 PSI versions.[7] DIG's D54 is listed for up to 6 GPM with 3/4 in MNPT on both ends.[3] Senninger lists the PRL at 0.5 to 8 GPM and the PRLG at 0.5 to 7 GPM.[2] DIG's adjustable regulators come in 12 to 35 psi (white, 18-008) and 28 to 60 psi (red, 18-007).[8]
Rain Bird's PRF07530SX store page lists no flow range, so we give none for it.[4] The RBY figures belong to the RBY models, not to the PRF07530SX.
Will a regulator work with only a few emitters?
Add up the flow of every emitter on the zone and compare it with the regulator's minimum. Rain Bird's 3/4 in RBY starts at 0.20 gpm, which is 12 GPH.[6] A handful of 0.5 GPH drippers falls below that. If your total is under a regulator's minimum, choose one rated for lower flow.
Why does my gauge read high after the regulator?
Because the water is not flowing. Senninger explains that with a standard regulator and a closed shut-off downstream, the inlet pressure can equalize across the regulator; a standard regulator is not a no-flow pressure limiter.[2] Read the gauge with the zone running. That is flowing pressure; the reading with everything closed is static pressure.
The same effect is why DIG warns that its D54 must not be left under constant static pressure.[3]
Maker scope
- Senninger says its regulators are recommended for outdoor use only and are not NSF certified.[2] That statement covers Senninger's regulators only.
- Mister Landscaper says its regulators should not be used inside a house or anywhere a leak might damage something.[9]
- We could not read Hunter's regulation guide, so we report no Hunter guidance.
Regulators that fit this decision
Picks that fit3 products
For a hose-thread faucet head, choose the Rain Bird HT07525PS (25 psi, 3/4 in FHT x MHT) or the Orbit 67738 3-in-1 (20 psi, 3/4 in FHT inlet, 1/2 in Drip-Lock outlet).
More on choosing
Choose the Rain Bird PRF07530S (30 psi, 3/4 in MPT both ends; listed by Rain Bird's store as PRF07530SX) only with pipe-thread adapters.
Hose-thread pressure regulator
Rain Bird HT07525PS 3/4 in FHT x MHT 25 psi pressure regulator
Pipe-thread filter-regulator
Rain Bird PRF07530S 3/4 in MPT pressure-regulating filter (30 psi, 200 mesh)
3-in-1 faucet adapter for Drip-Lock
Orbit 67738 3‑in‑1 faucet adapter (3/4 in FHT, 150 mesh filter, 20 psi regulator, 1/2 in Drip-Lock)
On Amazon, check that "Ships from" and "Sold by" show Amazon.com or the brand before you order.[10]
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Questions
Do I need a pressure regulator for drip irrigation?
Usually. DIG says most drip systems work best between 20 and 50 psi and names high pressure as the typical reason a drip system functions improperly.[1]
What PSI should a drip regulator be?
One inside the range of every part downstream. Makers sell drip regulators at outlet pressures such as 25 PSI (DIG D54) and 30 psi (Rain Bird PRF07530SX).[3][4]
Why does my gauge read high after the regulator?
With no flow, inlet pressure can equalize across a standard regulator, Senninger explains. Read the gauge with the zone running.[2]
Will a regulator work with only a few emitters?
Only if your total flow reaches its minimum. Rain Bird's 3/4 in RBY, for example, is rated for 0.20 to 5.0 gpm.[6]
How much higher should inlet pressure be than outlet pressure?
Senninger recommends at least 5 psi more at the inlet than the expected outlet pressure, for its regulators.[2]