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Quick answer from a licensed plumber: If your static pressure is over 80 psi, the plumbing code (IPC 604.8) requires a PRV; buy the Zurn Wilkins NR3XL. The 3/4 in. is sold by Amazon, adjusts from 15 to 75 psi and services in line. Pick the Watts LFN45B for sweat copper, the Watts LF25AUB-Z3 for a threaded Watts valve, and the Cash Acme EB45 for push-to-connect or crimp ends. With a tank water heater, the code also requires thermal expansion control once a PRV is in, so add an expansion tank.
Our pick for most houses: the Zurn Wilkins NR3XL, sold by Amazon in 3/4 in. Check the Zurn Wilkins NR3XL on Amazon
A water pressure regulator, or pressure reducing valve (PRV), sits where the water service enters the house and holds the pressure behind it to a set point. Zurn says high pressure wears pipes, faucets and appliances, and can lead to breakage and flooding. The valves below are whole-house PRVs for 3/4 in. and 1 in. service lines. The small brass regulators sold for RV hoses are a different product and are not covered here. If you are replacing a PRV you already have, start with our PRV replacement by brand guide.
Pressure Reducing Valves Compared
| Valve | Max inlet | Adjust range | Factory setting | Max water temp | Maker warranty |
|---|---|---|---|---|---|
| Zurn Wilkins NR3XL | 400 psi | 15-75 psi | 50 psi | 140°F | 12 months |
| Watts LF25AUB-Z3 | 300 psi | 25-75 psi | 50 psi | 180°F | 1 year |
| Watts LFN45B | 400 psi | 25-75 psi | 50 psi | 180°F (listing) | 1 year |
| Cash Acme EB45 | 400 psi | 10-70 psi | 45 or 60 psi | 180°F | not found |
From the Zurn, Watts and Cash Acme documents listed below, read on September 29, 2026. Max inlet figures are the makers’ ratings for the 3/4 in. and 1 in. sizes on this page. The Zurn 3/4 in., LFN45B and Cash Acme listings were sold by Amazon.com; the Zurn 1 in. listing’s seller switched between Amazon.com and a third-party seller, and the LF25AUB-Z3 listing was sold by a third-party seller.
Check Your Pressure Before You Buy
What the code and the makers say
The 2024 International Plumbing Code, which Georgia has used with state amendments since January 1, 2026 (none to this section), says that where static pressure in a building is over 80 psi, an approved PRV conforming to ASSE 1003 or CSA B356, with a strainer, shall be installed to hold the building piping to 80 psi or less (IPC 604.8). Zurn says the same. Watts’ model specification is stricter: install one where main pressure exceeds 60 psi and reduce it to 50 psi or lower. Your local code is what counts, so read the static pressure at a hose bib with a gauge before buying. Watts sells a gauge that records the highest reading while it is left on, which catches overnight spikes.
Thermal expansion comes with it
A tank water heater makes the water expand every time it heats. The plumbing code treats a PRV like a check valve here: where a storage water heater is fed through a check valve, pressure reducing valve or backflow preventer, IPC 607.3 requires a thermal expansion control device on the heater’s cold supply, downstream of those valves. Georgia’s 2024 version, in force since January 1, 2026, also puts it downstream of the shutoff valves and says an expansion tank must sit at least 18 inches, in developed length, from the heater’s cold inlet. The code also says the water heater’s relief valve must not be used to control thermal expansion (IPC 504.4). All four valves here have a bypass or back-pass check, but Watts says its bypass only keeps house pressure from rising more than 10 psi above street pressure. With 120 psi at the street, that still allows about 130 psi in the house against a 50 psi setting (our arithmetic). Zurn’s install sheet also calls for an expansion relief valve or tank. Budget for a water heater expansion tank and make sure the T&P relief valve works.
Zurn Wilkins NR3XL Pressure Reducing Valve
3/4 in. or 1 in. double union FNPT (34-NR3XLDU, 1-NR3XLDU) · max inlet 400 psi (1/2 to 1-1/4 in.) · adjustable 15 to 75 psi · factory set 50 psi · max 140°F · integral stainless steel strainer · integral bypass · ASSE 1003, cUPC, CSA B356 · 12-month warranty from purchase
The NR3XL is Zurn Wilkins’ compact residential PRV. Zurn says it suits systems that need “frequent cleaning of sediment and debris” because the stainless strainer is built in. Zurn says the cartridge can be serviced without removing the valve from the line, and it sells repair kits by size. Zurn lists the adjustable range as 15 to 75 psi from a factory setting of about 50 psi, with inlet pressure up to 400 psi on the 1/2 to 1-1/4 in. sizes. The 3/4 in. listing is sold by Amazon.com. The 1 in. listing switched between Amazon.com and a third-party seller during our checks on September 29, 2026, and is not linked now (see the note below).
Zurn’s documents differ on thermal expansion. The spec sheet says the integral bypass “prevents buildup of excessive system pressure caused by thermal expansion.” The installation sheet says pressure rise from a heating water heater is “a natural consequence”, and that an expansion relief valve or expansion tank set at the PRV outlet pressure “must be installed.” Plan on the tank. Zurn’s warranty is short: 12 months from purchase, with the valve returned freight prepaid. Its sheet says the valve should be installed by a qualified licensed plumber. The 140°F limit is the lowest of the valves here.
- 3/4 in. sold and shipped by Amazon
- Cartridge design; Zurn sells repair kits by size
- Adjusts from 15 to 75 psi, per Zurn
- Integral strainer and bypass, per Zurn
- Warranty is 12 months from purchase (Zurn install sheet)
- Max water temperature 140°F, lowest of these valves
- Zurn’s spec sheet and install sheet disagree on whether the bypass is enough for thermal expansion
Verdict: The PRV to buy for most houses: Amazon-sold, easy to service and fully documented. Add an expansion tank at the water heater.
Not linked: Zurn Wilkins NR3XL (1 in.) — on 10/4/2026 the Amazon listing was sold by a third-party seller, not by Amazon or the maker. We re-check listings every week.
Watts LF25AUB-Z3 Pressure Reducing Valve
3/4 in. union FNPT inlet x FNPT outlet · max inlet 300 psi · adjustable 25 to 75 psi · standard setting 50 psi · 33 to 180°F · integral stainless steel strainer · replaceable seat module · sealed spring cage (Z3) · ASSE 1003, CSA B356, IAPMO · 1-year warranty from original shipment
The LF25AUB-Z3 is Watts’ standard lead-free house PRV. Watts builds it with a union inlet, a stainless strainer you can clean in line, a replaceable seat module and a diaphragm Watts rates for hot water. The temperature range is 33 to 180°F. Watts offers suffixes for solder, PEX, quick-connect, press and double-union ends, and high (75 to 125 psi) and low (10 to 35 psi) spring ranges. Watts says the valve is not for direct burial; outdoors or in a pit, it belongs in a meter box or vault.
Watts says the built-in bypass keeps downstream pressure from rising more than 10 psi above supply. It also says the bypass will not stop the water heater’s relief valve from opening above 150 psi. When a check valve or backflow preventer closes the system, Watts says, “You must make provisions for pressure relief protection.” We found no Amazon-sold or Watts-sold listing for the 3/4 in. LF25AUB-Z3. The linked one is sold by New World Gas Products, a third-party seller, and the listing names the Watts model. Several listings nearby use “LF25AUB-Z3” in the title without the Watts brand; skip those.
- Rated 33 to 180°F, per Watts
- Strainer and seat module service in line, per Watts
- Many end-connection and spring-range options
- Sealed spring cage for pit or outdoor meter-box installs
- Sold by a third-party seller, not Amazon
- Max inlet 300 psi, lower than the NR3XL and LFN45B
- Warranty is one year from original shipment, per Watts
- Look-alike listings use the model number without the brand
Verdict: The pick when you want Watts’ standard house valve with a threaded union inlet, or a Watts end connection the LFN45B listing does not offer.
Watts LFN45B Pressure Reducing Valve (3/4 in. Solder Union)
3/4 in. double union solder (LFN45BM1-DU-S) · max inlet 400 psi · adjustable 25 to 75 psi · factory set 50 psi · integral stainless steel strainer · thermal expansion bypass · sealed spring cage · 33 to 180°F per the Amazon listing · 1-year warranty from original shipment
This LFN45B listing is the double-union solder version, and it is sold by Amazon.com. Watts rates it for supply pressure up to 400 psi and a 25 to 75 psi range, preset at 50 psi. Watts says the strainer and seat-and-stem module lift out once you shut off the supply, back off the adjusting screw and remove the spring cage. Watts’ LFN45B instructions give no temperature range; the Amazon listing gives 33 to 180°F.
Its instructions carry the same Watts bypass and relief language as the LF25AUB-Z3. The bypass holds downstream pressure to 10 psi over supply. Watts calls the system closed when a check valve or backflow preventer is on the supply, and says a relief valve such as its 530C or Governor 80, or a potable expansion tank, may be required. The code goes further: with a tank water heater, a PRV alone is enough to require thermal expansion control (IPC 607.3), and the water heater’s own relief valve does not count (IPC 504.4). Watts says the valve should be installed by a licensed contractor to local code. If you are swapping an old N45B or a Wilkins 70XL, our PRV replacement by brand guide matches old to new model numbers.
- Sold and shipped by Amazon
- Double union solder ends for copper lines
- 400 psi max inlet, per Watts
- Strainer and module service in line, per Watts
- Solder ends: you need to sweat it in, or pick a threaded model
- Temperature range comes from the Amazon listing, not Watts’ instructions
- Warranty is one year from original shipment, per Watts
Verdict: The pick for a sweat-copper service line when you want the Watts valve sold by Amazon.
Cash Acme EB45 Pressure Regulating Valve
3/4 in. in NPT double union, push-to-connect or crimp ends · outlet range 10 to 70 psi · max inlet 400 psi (1/2 to 1 in.) · up to 180°F · stainless steel strainer screen · inbuilt back-pass check · ASSE 1003, CSA B356 · factory setting: see below
The EB45 is Cash Acme’s half-cartridge regulator. It keeps a separate spring chamber and adjusting screw, and the working parts lift out as a module, per Cash Acme. The three linked versions are all 3/4 in. and all sold by Amazon.com: double-union NPT, a push-to-connect version that Cash Acme’s listing calls SharkBite-compatible, and a crimp version. Cash Acme lists a 10 to 70 psi outlet range, water up to 180°F and inlet pressure up to 400 psi on the 1/2 to 1 in. sizes.
The factory setting is unclear. Cash Acme’s 2019 specification says 45 psi. These listings carry model numbers ending in “-60” and say “rated to 60 PSI.” Set it with a gauge either way. The NPT and crimp listings’ bullets also describe push-in teeth and an O-ring, which belongs to the push-to-connect version. Trust the model number, not that bullet. Cash Acme’s documents describe an “inbuilt back-pass check” but say nothing about expansion tanks, and we found no warranty terms in the documents we read.
- Sold and shipped by Amazon in three 3/4 in. connection styles
- Push-to-connect version needs no soldering or threading
- Lowest outlet setting here: down to 10 psi (Cash Acme)
- Rated to 180°F, per Cash Acme
- Factory setting differs between the 2019 spec (45 psi) and the listings (60 psi)
- No warranty terms found in Cash Acme’s documents
- NPT and crimp listings have a wrong bullet about push-in teeth
- Top of range is 70 psi, lower than the others
Verdict: The pick for PEX or quick repairs where a push-to-connect or crimp PRV saves a soldered joint.
I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.
Before You Buy
- Measure static pressure. Use a hose-bib gauge with nothing running, and again at night. Zurn’s test also has you record the pressure while a fixture flows.
- Match the line size. Zurn says that when actual water demand is unknown, the valve should be no smaller than the existing pipe. It also warns that oversizing and undersizing both cause wear and noise.
- Match the connection. Threaded, solder, PEX, crimp and push-to-connect ends all exist. Buying the right end saves an adapter and a joint.
- Plan the expansion tank with the PRV. With a tank water heater, the code calls for thermal expansion control once the supply passes through a PRV, check valve or backflow preventer (IPC 607.3). Buy and install the tank at the same time.
- Leave room to service it. Watts and Zurn both say to install the valve where it is accessible for cleaning, service and adjustment.
Install and Adjustment Notes
- Release pressure first. Zurn says to close the shutoff valve upstream of the PRV, then open a faucet in the house to remove line pressure before servicing. Cash Acme says to close the isolating valves on both sides. On a Zurn NR3XL, loosen the adjusting-bolt lock washer slowly and relieve any trapped pressure under the sealed cage before removing the bell. See how to shut off your water main.
- Licensed installer. Zurn says the valve should be installed by a qualified licensed plumber; Watts says a licensed contractor, to local codes. Permits are set locally: Georgia’s 2026 amendments delete the code’s administration chapter and leave permits to cities and counties, so ask your building department whether the PRV or expansion tank needs a permit.
- Flush and orient. All three makers say to flush the supply line of scale and debris before installing, and to point the arrow on the body in the direction of flow. Zurn and Watts allow any orientation.
- Set it with a gauge. Zurn and Watts both say to verify the setting with a pressure gauge each time you adjust, and Zurn says the gauge goes downstream of the valve. The code lets lines to outdoor faucets skip the PRV (IPC 604.8 exception), so a hose bib piped ahead of the valve still reads street pressure; use a hose connection on the house side. Clockwise raises pressure on all three makers’ valves. Watts and Zurn say not to bottom out the adjusting screw or bolt.
- Clean the strainer. Zurn requires annual inspection and maintenance of plumbing system components. It says to call a licensed plumber if you are not qualified to do it.
- Very high supply pressure. Zurn recommends two regulators in series when the reduction is more than 3 to 1 or inlet pressure is above 150 psi.
FAQ
Do I need a water pressure regulator?
Check your pressure first. The plumbing code (IPC 604.8) requires a PRV where static pressure in the building is over 80 psi, and Zurn says the same. Watts’ model specification calls for one where main pressure exceeds 60 psi, reduced to 50 psi or lower. Your local code decides. A hose-bib gauge tells you where you stand; see our water pressure gauge picks.
What should I set my pressure reducing valve to?
No higher than 80 psi static, the code limit (IPC 604.8); Watts’ specification calls for 50 psi or lower. All four valves here ship near 50 psi (Zurn, Watts) or 45 to 60 psi (Cash Acme, see above). Zurn and Watts both say to use a pressure gauge any time you adjust the valve, and Zurn says the gauge goes downstream, on the house side. Zurn says to open a downstream faucet when lowering the setting, and not to bottom out the adjusting bolt.
Do I need an expansion tank with a PRV?
With a tank water heater, yes. IPC 607.3 (in Georgia, an amended version in force since January 1, 2026) requires a thermal expansion control device on the heater’s cold supply whenever that water passes through a pressure reducing valve, check valve or backflow preventer. Zurn’s install sheet also says an expansion relief valve or expansion tank “must be installed,” though its spec sheet credits the bypass alone. The water heater’s temperature and pressure relief valve does not count: the code says it must not be used to control thermal expansion. See our water heater expansion tank guide.
Why does my pressure creep up after a PRV?
Watts lists three causes: thermal expansion, pressure creep or dirt on the seat. Its test is to open a cold tap briefly; if pressure drops right back to the setting, it was thermal expansion. Zurn says to watch a gauge for 10 minutes; a slow climb means the valve needs cleaning, and a jump to supply pressure means repair or replacement. See water pressure spikes at night.
Will a pressure reducing valve stop water hammer?
Zurn lists water hammer among the problems a PRV helps prevent on irrigation systems, and says lower pressure reduces wear on pipes and fixtures. Plumber’s note, not from a maker: for a bang when one valve shuts, a water hammer arrestor at that fixture is the direct fix. See our water hammer arrestor picks.
Why Trust Plumbing Picks
Plumbing Picks is written by a licensed Georgia journeyman plumber. Every spec here comes from the maker documents listed below or the Amazon listings we link; nothing comes from hands-on testing. On September 29, 2026, the 3/4 in. Zurn Wilkins NR3XL, Watts LFN45B and Cash Acme EB45 listings were sold by Amazon.com and in stock; the 1 in. NR3XL listing shipped from Amazon, and its seller switched between Amazon.com and a third-party seller across our checks that day. No Amazon-sold or Watts-sold listing existed for the 3/4 in. Watts LF25AUB-Z3, so that link goes to a third-party seller offering the Watts model, in stock when we checked. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.
Sources
- Zurn Wilkins: NR3XL product page, NR3XL specification sheet, NR3XL installation, maintenance and warranty sheet, NR3XL sell sheet, Principles of Pressure Regulation brochure
- Watts: LF25AUB-Z3 product page, engineering specification ES-LF25AUB, installation instructions IS-LF25AUB-Z3 (includes the warranty)
- Watts: LFN45B product page, LFN45B installation instructions (includes the warranty)
- Cash Acme: EB-45 sales and specifications (2019), EB45 installation instructions I0519, EB45 specification sheet CAEB25PRV0621 (copy hosted by a retailer)
- 2024 International Plumbing Code: 604.8 Water pressure-reducing valve, 607.3 Thermal expansion control, 504.4 Relief valve, Georgia DCA: state amendments to the 2024 IPC (Chapter 1 deleted, 607.3 as amended; effective January 1, 2026)
- Amazon listings for the Zurn Wilkins NR3XL, Watts LF25AUB-Z3, Watts LFN45B and Cash Acme EB45 (linked above)
Bottom Line
Measure your pressure first; the code (IPC 604.8) requires a PRV above 80 psi static, and Watts’ spec starts at 60 psi. The Zurn Wilkins NR3XL is the valve to buy for most houses. Choose the Watts LF25AUB-Z3 for a threaded Watts valve, the Watts LFN45B for sweat copper, and the Cash Acme EB45 for push-to-connect or crimp. Shut the water and relieve pressure before any work, set it with a gauge on the house side of the valve, and plan an expansion tank: with a tank water heater, the code requires thermal expansion control once a PRV is in (IPC 607.3).