Pressure Reducing Valves

What Are Pressure Reducing Valves?

A pressure reducing valve (PRV) — sometimes called a pressure regulating valve — is one of the most important yet overlooked components in a residential or commercial plumbing system. Installed on the main water supply line, a PRV automatically reduces the incoming supply pressure from the municipal main to a safe, steady level before it reaches your pipes, fixtures, and appliances. Without one, excessively high water pressure can silently damage everything from faucets and showerheads to water heaters, dishwashers, and washing machines over time.

Why Water Pressure Regulation Matters

Municipal water supply pressures can vary dramatically and often arrive at a building well above the safe range for residential plumbing systems. Most household plumbing is designed to operate comfortably between 40 and 80 PSI. Sustained pressure above that threshold accelerates wear on pipe joints, causes water hammer, shortens the lifespan of appliances, and can even void manufacturers' warranties. A quality PRV maintains a constant outlet pressure across a wide range of fluctuating inlet supply pressures, acting as a silent guardian for your entire plumbing infrastructure.

Key Considerations When Choosing a Pressure Reducing Valve

• Connection Size & Type: PRVs are available in common sizes such as 1/2", 3/4", and 1" NPT or push-to-connect fittings. Match the valve to your supply line diameter for proper flow.
• Inlet Pressure Range: Make sure the valve is rated to handle your incoming supply pressure. Some models handle up to 250 PSI or higher on the inlet side.
• Adjustability: Look for valves with an accessible adjustment mechanism — dial-set designs allow you to fine-tune the outlet pressure without the need for additional gauges.
• Material & Certifications: Brass and bronze bodies offer excellent durability and corrosion resistance. For potable water applications, look for compliance with NSF/ANSI 61 and NSF/ANSI 372 (lead-free standards), as well as ASSE 1003 or IAPMO listings.
• Application Type: Residential PRVs differ from industrial-grade steam and fluid control regulators. Know whether you need a valve for domestic water, irrigation, steam distribution, or industrial process control before purchasing.

Top Brands in Pressure Reducing Valves

Resideo by Honeywell is a leading name in residential and commercial water pressure regulation. Their valve lineup — including the popular DialSet series — features brass and bronze bodies with stainless steel internal components, and models are compliant with NSF/ANSI 61 and NSF/ANSI 372 for safe use in potable water systems. The DialSet design includes a built-in adjustment dial that eliminates the need for a separate pressure gauge during setup, making installation straightforward for both professionals and experienced DIYers.

Spence Engineering Company brings a deep industrial heritage to the pressure reducing valve category. Founded in 1926, Spence pioneered the normally closed, external pilot-operated packless pressure regulator — a design that remains the foundation of their product line today. Their pilot-operated E Main valves are engineered for steam distribution, process control, and district heating systems, and are available in sizes from 3/8" to 12" in cast iron and cast steel bodies, making them a go-to solution for demanding institutional and industrial applications.

Installation & Maintenance Tips

PRVs should typically be installed on the main cold water supply line, after the main shutoff valve and before any branch lines. Many professionals recommend pairing a PRV with a thermal expansion tank when the system is closed, since reducing pressure without allowing for thermal expansion can create excess stress in water heaters. Regularly checking the outlet pressure with a gauge and inspecting the internal strainer screen for debris will help ensure years of reliable service.