House has 95 psi static at the hose bib.

Yes, you need a PRV. 95 psi static exceeds the 80 psi maximum allowed by IPC 604.8 / UPC 608.2 / IRC P2903.3.1. Most fixtures and appliances are rated for 80 psi max; higher pressure voids warranties and accelerates failure.

What changes when you install it:

1. Thermal Expansion Control (Mandatory): A PRV creates a closed system. Heating water builds pressure with nowhere to go. You must install a properly sized expansion tank on the cold inlet to the water heater (IPC 607.3.2 / UPC 608.3). Pre-charge tank air pressure to match your new PRV setting (e.g., 55–60 psi) before installation.
2. Set Pressure: Adjust PRV to 55–60 psi. Do not leave at factory default (often 45–50 psi). Verify with a gauge on a hose bib downstream.
3. Flow/Volume Drop: Expect slightly lower flow at fixtures, especially if old galvanized piping is corroded. A 3/4" PRV on a 3/4" line minimizes this.
4. Irrigation: If the irrigation tee is upstream of the PRV (common), heads will still see 95 psi. You may need a separate PRV or pressure-regulating heads for that zone.
5. Maintenance: Clean the PRV strainer screen annually. They fail closed (no water) or open (full street pressure). Test annually.
6. Water Heater T&P Valve: If it was weeping before, it may stop. If it weeps after, the expansion tank is undersized, missing, or not pre-charged.

Install: Shut off main → Cut in PRV (union + shutoffs recommended) → Install expansion tank → Pressurize tank → Open main → Set PRV → Verify pressure.

Yes, you need a pressure reducing valve (PRV).

Why: Residential water pressure should be 40–80 psi per IPC Section 604.8 and UPC Section 608.2. At 95 psi static, you exceed safe limits, risking:

• Premature failure of fixtures, water heaters, and appliance valves (washing machines, dishwashers)
• Leaking faucets and toilet fill valves
• Water hammer and pipe stress
• Voided warranties on plumbing appliances

What changes after installing a PRV:

1. Pressure drops to setpoint (typically 50–60 psi, adjustable via screw on PRV).
2. Flow may feel slightly reduced at fixtures — this is normal; the system is now operating safely.
3. Thermal expansion tank may be required if you have a closed system (check valve, PRV, or backflow preventer downstream). Heated water expands — without an expansion tank, pressure can spike dangerously. Check local code (IPC 607.3).
4. PRV must be installed on the main supply line, after the meter and before the first fixture, accessible for service (IPC 608.3).
5. Periodic maintenance: PRVs can fail or clog; test pressure annually with a gauge at a hose bib.

Do it: Install a PRV (e.g., Watts LFN45BM1 or similar) with a thermal expansion tank if your system is closed. If unsure about backflow prevention or expansion needs, consult a licensed plumber — improper installation can cause pressure spikes or contamination risks.

Note: If your municipality supplies water >80 psi, they may require a PRV at the meter — check with your water department.