Information Guide ·13 min read

Water Pressure Regulator: Which One Do You Have, and What Rebuild Kit Fits?

By Thomas Kwayne · November 9, 2026 · Fact-checked against manufacturer documentation and authoritative trade sources.

A household water pressure regulator on a service line with its nameplate and adjustment screw visible, illustrating how to identify a water pressure regulator and its rebuild kit

Your water pressure regulator may be creeping, noisy or simply old, and the parts listings all say “PRV repair kit.” Order from the wrong one and you pay for a kit that does not fit, then wait for a return. The kit depends on the maker, the complete model, the nominal valve size and the pressure-range variant, and a kit made for one size can be wrong for the next.

The short answer: find the valve near your service shutoff or meter, photograph it, read the maker and full model off the plate or body, and then match all of it to the maker’s repair table. This page covers household pressure-reducing valves from Watts, Zurn Wilkins, Cash Acme and Resideo/Braukmann. It does not cover faucet cartridges, shower valves, boiler-feed regulators or water-heater relief valves.

Find the Regulator and Photograph It

A household regulator is commonly found near the service shutoff or the meter, according to Howard County and the City of Lincoln. That location helps you find the device. It does not tell you which repair it needs, so treat finding it and diagnosing it as two separate jobs.

Take photographs before you shop:

the whole valve and the piping on both sides;
any readable plate or body marking, with every number and suffix kept;
the adjustment assembly on top;
both connections.

Do not loosen a bonnet, union, plug or adjustment assembly just to expose a marking. Watts and Zurn service instructions call for pressure to be relieved before the relevant assemblies are opened (Watts LF25AUB-Z3 instructions, Zurn NR3XL instructions).

Read the Markings You Can See

Collect four facts: the maker, the complete model designation, the nominal size, and the pressure-range variant. Watts asks for the ordering code, size, type number and nameplate model (Watts). Zurn publishes size-specific repair-kit numbers in its NR3XL instructions and connection-specific dimension tables in its NR3XL specifications. “Watts regulator” or “Wilkins three-quarter” is not enough to order from.

Marking locations vary by maker, and no single spot holds for every valve:

Watts: according to Watts’ marking standard, pressure-regulator date codes go preferentially on the body near the size and model markings, with the nameplate as an alternative. The LFN45B-M1 drawing places its nameplate at the top adjustment assembly (Watts marking standard, LFN45B-M1 instructions).
Zurn Wilkins: Zurn’s 70XL drawing shows a nameplate above the bell and “WILKINS” and “70” on the body (Zurn 70XL instructions). A cast “70” is useful family evidence, but it does not supply every ordering detail. We did not find a universal location for an NR3XL serial label.
Cash Acme and Resideo: we found no external marking that reliably separates an EB45 Classic from a Compact. For the Resideo DS06, photograph the adjustment head, dial ring, body, lower bowl and whatever designation survives (Cash Acme catalog, Resideo DS06 instructions).

Date Codes and Serial Numbers Do Not Pick the Kit

Watts documents a date-code format of YYWWXX: year, manufacturing week, and a supplier code, with single-letter exceptions for certain factories. Its example, 1012GJ, is the twelfth week of 2010 from supplier GJ (Watts marking standard). The same standard covers separate product, component and packaging codes, so a packaging date is not the production date of the valve on your wall.

That code is a traceability system. It is not a public lookup that returns a kit. We found no public decoder for residential regulator serial numbers from Zurn, Cash Acme or Resideo, so do not guess a year or week from an unfamiliar code. Keep it and pass it to the maker if you ask for help. Manufacturer repair tables, which match a model and size to a kit number, are what decide the order (Watts instructions, Cash Acme repair kits).

Water Pressure Regulator Repair Kits: The Fit Chart

Each row below comes from a maker’s own catalog, specification sheet or instructions. Where a source states no exclusion, the table says so, and that does not mean the kit is universal. A repair kit, a filter, a valve insert, a retrofit adapter and a complete regulator are different purchases. Keep the size and the pressure variant in your lookup.

Maker	Model it fits	Part number	Qualification	Source
Watts	LF25AUB / LF25AUB-Z3, 1/2 inch	0864941	Size-specific; no further exclusion stated	Watts 2026 catalog
Watts	LF25AUB / LF25AUB-Z3, 3/4 inch	0864943	Correct number even though it follows the 1-inch kit numerically	Watts 2026 catalog
Watts	LF25AUB / LF25AUB-Z3, 1 inch	0864942	Do not interchange with 0864943	Watts 2026 catalog
Watts	LF25AUB / LF25AUB-Z3, 1-1/4 inches	0864944	Size-specific	Watts 2026 catalog
Watts	LF25AUB / LF25AUB-Z3, 1-1/2 inches	0864945	Size-specific	Watts 2026 catalog
Watts	LF25AUB / LF25AUB-Z3, 2 inches	0864946	Size-specific	Watts 2026 catalog
Watts	LFN45B-M1, 1/2 to 1 inch	0006960	Seat and stem module	Watts LFN45B-M1 instructions
Zurn Wilkins	NR3XL standard, 1/2 inch	RK12-NR3XL	Keep size and pressure variant	Zurn NR3XL instructions
Zurn Wilkins	NR3XL standard, 3/4 inch	RK34-NR3XL	Standard range	Zurn RK34-NR3XL
Zurn Wilkins	NR3XL standard, 1 inch	RK1-NR3XL	The high-range kit has a different number	Zurn NR3XL instructions
Zurn Wilkins	NR3XL standard, 1-1/4 inches	RK114-NR3XL	Size-specific	Zurn NR3XL instructions
Zurn Wilkins	NR3XL standard, 1-1/2 inches	RK112-NR3XL	High-range entry is “N/A” in this table	Zurn NR3XL instructions
Zurn Wilkins	NR3XL standard, 2 inches	RK2-NR3XL	High-range entry is “N/A” in this table	Zurn NR3XL instructions
Zurn Wilkins	NR3XL 3/4-inch high-range sealed-cage variant	RK34-NR3XLHRSC	Separate from the standard kit	Zurn NR3XL instructions
Zurn Wilkins	70XL, 3/4 inch	RK34-70XL	Legacy applications are listed separately	Zurn 70XL instructions, Zurn Model 70
Zurn Wilkins	70XL, 70DU and 70, 1 inch	RK1-70XL	Zurn names the legacy applications	Zurn RK1-70XL
Zurn Wilkins	All 3/4- and 1-inch 20XL configurations	RK34-1-20XL	Internal kit, not a retrofit adapter	Zurn 20XL specifications
Zurn Wilkins	600XL, 2 inches	RK2-600XL	The high-range kit differs	Zurn 600XL instructions
Cash Acme	EB45 Compact, 1/2 to 3/4 inch	23870	Does not settle the 22595 question below	Cash Acme catalog
Resideo/Braukmann	Low-lead DS06 / FK06, 1/2 to 3/4 inch	D06FA-1/2	Valve insert (the filter insert is a separate part); availability is unsettled (below)	Resideo DS06 parts table, SupplyHouse listing
Resideo/Braukmann	Low-lead DS06, 1 to 1-1/4 inches	D06FA-1B	Regulating insert	Resideo DS06 parts table
Resideo/Braukmann	Low-lead DS06, 1 to 1-1/4 inches	ES06F-1B	Filter insert; does not replace the regulating insert	Resideo DS06 parts table
Resideo/Braukmann	Historical D05, 1/2 to 3/4 inch	K05A1009	Historical application; compatibility with the current DS05 is not established	Resideo D05 instructions
Zurn Wilkins	Specified 1-inch NR3 / NR3XL / BR4 installations converted to a 20XLDULU	RFK1-NR3-20XL	Retrofit adapter kit; the new regulator is bought separately	Zurn 20XL specifications

A few more entries are documented but carry narrower support. Watts’ N55B-M1 instructions list kit 0006960 for the N55B-M1 and LFN55B-M1 in 1/2 to 1 inch (Watts N55B-M1 instructions), and Watts’ 2026 catalog lists the same ordering code for the LFN45B/LFN55B-EZ in 3/4 to 1 inch (Watts 2026 catalog). According to Zurn’s 70XL repair table, RK12-70XL fits the 1/2-inch 70XL, and the DU-series kits RK114-70XLDU, RK112-70XLDU and RK2-70XLDU cover 1-1/4, 1-1/2 and 2 inches. Zurn’s kit guide lists high-range NR3XL kits RK12-NR3XLHRSC, RK1-NR3XLHRSC and RK114-NR3XLHRSC (Zurn kit guide). Cash Acme’s kit table lists 23871 for the EB45 in 1-1/4 to 2 inches, and 23148 for the EB25 in 1/2 to 1 inch (Cash Acme kit table).

Matched your regulator to a row in the chart? Confirm the exact kit against the maker's own instructions for your model, size and pressure range before you buy, because a similar-looking regulator does not decide it:

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Where the Sources Disagree

Four points are unsettled in the makers’ own documents. We list both sides and do not pick one.

Cash Acme 22595. Cash Acme’s catalog calls 22595, for 1/2 to 1-inch EB45 applications, the “Classic Model.” Cash Acme’s current repair-kit page labels it Compact. SupplyHouse lists it as a Classic-model cartridge (SupplyHouse). The Classic reading has more support, but if you cannot tell which EB45 generation you own, confirm with Cash Acme before ordering, and do not treat 22595 as a universal EB45 cartridge.

NR3XL high-range setting limit. The Zurn-hosted sheet gives 15 to 125 psi. An older Zurn sheet hosted by Lowe’s gives 15 to 150 psi (older sheet). Use the document that matches your valve, and do not read the higher number as permission to adjust to it.

EB45 factory setting. Cash Acme’s historical catalog states 45 psi. Its current EB45 page states 60 psi and includes newer PVA models (Cash Acme EB45 page). Neither supports a single factory setting for every EB45.

D06FA-1/2 availability. SupplyHouse’s page documents the fitment (a valve insert for the DS06-1/2LF and DS06-3/4LF) and states the part was discontinued on November 27, 2021 (SupplyHouse). The product page Resideo’s dealer catalog once showed for this part no longer resolves, and Resideo’s DS06 parts table still names the insert. Neither source settles current stock, so confirm with the seller.

Appearance Narrows the Family, Not the Kit

A similar bell or a missing “XL” does not prove two valves interchange, or that they do not. Zurn’s NR3XL drawings show connection arrangements that can differ within one nominal size, and Zurn’s kit program lists legacy models under different names (Zurn NR3XL specifications, Zurn kit program).

Features worth photographing are the nameplate, the adjustment screw and locknut, the bell or spring cage, and the unions. Zurn’s NR3XL has a composite bell and its 70XL a bronze bell, and the Cash Acme EB25 shows a numerical setting indicator (see the Zurn 70XL page and Cash Acme EB25 page). These are comparison points. They are not brand signatures, and the remaining question is always the exact family, size and variant.

Look Up the Kit, or Test Before You Buy

Start with the maker’s model page, repair table or illustrated instructions. Watts, Zurn and Cash Acme all publish model pages or kit tables, and Resideo publishes a DS06 parts table. We found no automatic photograph or serial-number decoder. A search that works is the brand, the complete model, the nominal size and the words “repair kit.”

A kit may not be what you need. Zurn’s NR3XL maintenance sequence compares flowing and static pressure and watches the pressure for ten minutes. According to Zurn, slow creep leads to cleaning and retesting, and continued creep leads to repair. Resideo’s legacy D05 instructions explain that lower flowing pressure can be normal regulator behavior (Zurn NR3XL instructions, Resideo D05 instructions). One high reading, or an ordinary drop while water flows, does not prove the need for a kit.

If You Cannot Find the Brand or Model

We found no verified universal rebuild kit that crosses brands for these regulators. The tables list families, sizes and variants, so do not borrow a generic-kit shortcut from faucet repair. That is a limit of what we could find, not proof that no such product exists (Cash Acme kit table).

Send the photo set and every surviving marking to a plumbing supplier or a candidate maker. Watts, Zurn and Cash Acme each have contact routes, though none promises to identify a valve from a photograph. If identification stays uncertain or the kit cannot be sourced, ask for separate quotes for a repair and for a complete replacement.

Two cautions. A discontinued valve is not automatically unrepairable: Zurn names the 70XL as the replacement for the discontinued Model 70, and its RK1-70XL page expressly keeps legacy Model 70 applications (Zurn Model 70). And a retrofit can replace a rebuild. RFK1-NR3-20XL is an adapter for specified conversions that use a separately bought 20XLDULU. Matching nominal pipe size does not establish that the unions interchange (Home Depot listing).

When to Call a Plumber

Call one when identification means opening the regulator, when you cannot isolate it reliably, or when pressure testing is needed to separate a failed regulator from another problem. Zurn warns of trapped pressure during NR3XL service, and Resideo’s DS05 instructions call for a trained, experienced technician (Resideo DS05 instructions).

Ask for this in writing: identify the maker, complete model, nominal size, connection configuration and repair-kit number, and test whether cleaning, repair or replacement is indicated. We found no verified national price for an identification call. Two local examples show the terms vary. Bonfe advertises a $99 first 30 minutes, with additional charges beyond that and a waiver when it performs the work (Bonfe). Steinmetz describes a $99 basic visual diagnosis with limits on further investigation (Steinmetz). Neither guarantees a fixed price for a regulator visit.

What to Do Next

Write down the maker, the complete model, the nominal size and the pressure variant, and match all four to the maker’s repair table before you order. Model-specific removal methods, pressure-release steps and gauge checks come from your valve’s own instructions, so follow those rather than a general procedure. Watts requires a gauge when adjusting the LFN45B, for example, while county guidance on household adjustment does not spell out gauge verification (Howard County). Professional opinions vary on whether to clean, rebuild or replace after testing.

Can I find the right kit from a serial number?

No public decoder turned up for these makers. Watts documents a date-code format, but it traces manufacture and does not return a kit. The model, size and pressure variant decide the order.

Does the 3/4-inch Watts LF25AUB kit come after the 1-inch number?

Per Watts’ 2026 catalog, the 3/4-inch kit is 0864943 and the 1-inch kit is 0864942, and the two should not be interchanged.

Is there one rebuild kit that fits every brand?

We did not find one. The makers’ tables list kits by family, size and variant.

Can a discontinued Zurn Model 70 still be repaired?

Possibly. Zurn lists the 70XL as its replacement, and the RK1-70XL page names legacy Model 70 applications, so a discontinued model is not automatically unrepairable.

What is the RFK1-NR3-20XL?

It is a retrofit adapter kit for specified 1-inch NR3, NR3XL and BR4 installations converted to a 20XLDULU. The new regulator is bought separately.

Sources

Educational content only. Not a substitute for licensed professional advice. Local plumbing codes vary by jurisdiction. Use of any guidance from this guide is at your own risk.

Parts for this repair

As an Amazon Associate, plumbingbythebook earns from qualifying purchases. Links below are affiliate links — they cost you nothing extra.

Zurn Wilkins RK34-NR3XL 3/4-Inch Repair Kit (search by part number) — Zurn lists RK34-NR3XL as the standard-range 3/4-inch kit for the NR3XL. The high-range sealed-cage variant has a separate kit number, so check your valve's pressure variant before you order.
Cash Acme 23870 EB45 Compact Cartridge Kit (search by part number) — Cash Acme's 2020 catalog lists 23870 for the EB45 Compact in 1/2 to 3/4 inch. It does not settle the separate 22595 generation question, so confirm which EB45 you have before you order.

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