Pressure Discipline
Pressure Reducing Valve (PRV)
High pressure is a common hidden cause of leaks, broken heads, and valve failures. A PRV regulates the irrigation supply so the system can operate in a predictable, serviceable range.
Our discipline standard: target 65 PSI, tune for operational performance, and never exceed a 75 PSI regulated ceiling.
Recommended hardware: For common 1" service scenarios where we want union serviceability, see Caleffi 535 PRV (1" union). If you want an on-body gauge for faster verification and cleaner follow-up service, see Caleffi 535361HA (with gauge).
| Industry | Irrigation |
|---|---|
| Concept | Pressure reducing valve (PRV) / pressure regulation |
| SRMS scope | SRMS is optimized for typical 3/4"–1" service lines. A PRV is an optional add-on when source pressure is excessive; SRMS control commonly uses a master valve + flow meter. Larger service lines (>1") are in development. |
| Typical trigger | Consistently high static pressure (often noted above ~80 PSI) |
| Service fit | SRMS, Startup & Inspection, Tune-Ups & Repairs |
| Common hardware | Caleffi 535 PRV (1" union) (union-serviceable reference) |
| Gauge option | Caleffi 535361HA (with gauge) (1" NPTF; gauge supports verification and documentation) |
Why 85+ PSI is a problem (common locally)
In parts of the Rochester, MI area, we sometimes measure 85+ PSI at the irrigation supply — and we have also measured real-world sources as high as 105 PSI. That high source pressure can turn small defects into leaks quickly and can accelerate wear on valves, heads, fittings, and backflow-related components.
Water-use impact (85 PSI vs regulated 75/65)
Scoping tool: visualize the difference between high source pressure and regulated pressure. For best accuracy, use measured zone GPM. Calculations are approximate.
Defaults reflect common 3/4" and 1" residential/HOA system classes.
If unknown, estimate now and refine after inspection.
Optional: include backflow + fittings + piping loss.
Used only for pre-visit service-size estimates.
Illustrative: same zone, different pressures.
PRV installation process (what we do)
- Confirm pressure: measure static pressure and observe behavior under flow (zones running).
- Install location (standard): install the PRV in the irrigation downleg after the backflow prevention assembly (PVB), keeping both components serviceable and testable.
- Install + set: set to 65 PSI as the discipline target, then tune only as needed (ceiling 75 PSI regulated).
- Validate performance: re-test zones and look for improved reliability (less misting/overspray, fewer leaks, better valve behavior).
- Prioritize follow-ups: if high pressure has already caused recurring failures, we recommend the most cost-effective repairs first.
Package option: PRV downleg installation package (1" copper) (unionized PRV + test/tune for water discipline).
When a PRV is recommended
- Static water pressure is consistently high (commonly noted above ~80 PSI)
- Frequent broken heads, weeping valves, or recurring leaks
- Newer high-efficiency nozzles that prefer regulated pressure
What it protects
- Valves and diaphragms (less stress and weeping)
- Heads and seals
- Fittings and joints
PRV FAQs (service-first)
What counts as excessive pressure for irrigation?
We flag it when static readings are consistently above ~80 PSI or when symptoms show up (misting/fogging, overspray, recurring leaks, frequent head/valve failures). The more important check is pressure under flow on the highest-demand zone.
Why is 65 PSI the discipline target?
65 PSI gives a predictable working baseline so zones can be tuned cleanly. After regulation, we tune nozzles, arcs, radius, and programming to match the property and avoid runoff.
Why is 75 PSI the ceiling?
Above 75 PSI regulated, pressure becomes a repeat-failure multiplier. If a system seems to “need” more than 75 PSI to perform, we usually address nozzle selection, zone sizing, or hardware issues instead of pushing pressure.
Will a PRV reduce water usage?
Often. On many systems, reducing pressure reduces flow on non-pressure-compensating nozzles and reduces misting/runoff. The biggest savings typically come after regulation when we can tune coverage and runtimes more predictably.
How do you estimate flow when a meter is not available?
Best method is zone head counts + manufacturer nozzle charts. If measured GPM is not available yet, we start with a conservative service-size estimate and verify under flow during inspection.
Recommended hardware (service-first)
We keep PRV installs focused on serviceability (union access) and repeatable results (verify under flow, then tune zones). A common reference option:
- Caleffi 535 PRV (1" union) (common 1" class install)
- PRV down-leg package (1" copper) (scope + install pattern)
Want it installed?
We can measure pressure, confirm the best install location, and tune it to a safe range.
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