Best Pressure Washer Pumps in 2026: Replacement Pumps Compared
Quick answer: For most home gas washers with a horizontal 3/4 inch shaft, the Simpson 90028 (3,300 PSI, 2.4 GPM, about $120) is the best-value replacement pump. The AR RMW2.2G24-EZ suits vertical-shaft engines, and the CAT 4DNX27GSI is the triplex upgrade for heavy use. Match shaft size, shaft direction, PSI and GPM before you order. We have not tested them ourselves. Last updated: October 2026.
A worn pump is one of the most common reasons a gas pressure washer loses pressure, and replacing it usually costs far less than a new machine. This guide compares current replacement pumps using manufacturer specs and retailer listings, and explains how to choose one that fits your engine.
How did we choose these pumps?
We looked for pumps that are sold now by named retailers, have published PSI, GPM and shaft specifications, and come from manufacturers with parts support. We included one low-cost universal pump and say plainly where its specs are incomplete.
Pressure washer pump comparison
| Pump | Type | PSI / GPM | Shaft | Price |
|---|---|---|---|---|
| Simpson 90028 | Axial cam | 3,300 / 2.4 | 3/4 in horizontal | About $120 |
| Simpson 90029 | Axial cam | 3,400 / 2.5 | 3/4 in horizontal | About $160 |
| AR RMW2.2G24-EZ | Axial radial | 2,400 / 2.2 | 7/8 in vertical | About $130 |
| AR RMV2.5G30D-EZ | Axial radial | 3,000 / 2.5 | 3/4 in horizontal | About $226 |
| CAT 4DNX27GSI | Triplex | 3,000 / 2.7 | 3/4 in horizontal | About $458 |
| AR RSV4G40HDF40-EZ | Triplex | 4,000 / 4.0 | 1 in horizontal | About $355 |
| Comet AXD3025G | Axial | 2,500 / 3.0 | 3/4 in horizontal | About $440 |
Prices were checked at Home Depot and specialist pump retailers in October 2026.
What are the best pressure washer pumps?
1. Simpson 90028: best value for home gas washers
Made by OEM Technologies for Simpson, the 90028 is an axial cam pump rated at 3,300 PSI and 2.4 GPM with a thermal relief valve. It fits the horizontal 3/4 inch shaft found on most consumer engines. At about $120 it is the simplest fix for a failed pump on a 2,700 to 3,300 PSI machine.
2. Simpson 90029: more pressure for larger engines
The 90029 raises output to 3,400 PSI and 2.5 GPM and has an M22 outlet. Choose it if your original pump had similar ratings.
3. AR RMW2.2G24-EZ: best for vertical-shaft engines
Many budget washers use a vertical-shaft engine like a lawn mower. The Annovi Reverberi RMW2.2G24-EZ is made for them: 2,400 PSI, 2.2 GPM, a 7/8 inch vertical shaft, thermal relief included and a 140°F maximum inlet temperature. It is listed for 4 to 7 HP engines.
4. AR RMV2.5G30D-EZ: step-up axial pump
This AR pump delivers 3,000 PSI and 2.5 GPM on a horizontal 3/4 inch shaft. It costs more than the Simpson pumps but comes from AR’s main replacement range with wide parts support.
5. CAT 4DNX27GSI: best triplex upgrade
CAT Pumps is the name most often used on professional machines. The 4DNX27GSI is a direct-drive triplex plunger pump rated at 3,000 PSI and 2.7 GPM with a 3/4 inch hollow shaft. It costs about $458, but triplex pumps can be rebuilt with new seals and valves when they wear.
6. AR RSV4G40HDF40-EZ: best for 4,000 PSI machines
For 13 HP class engines with a 1 inch shaft, this AR triplex pump delivers 4,000 PSI and 4.0 GPM. It is listed for 11 HP and up, so it is not a fit for small engines.
7. Comet AXD3025G: high flow at lower pressure
The Comet AXD3025G is rated at 2,500 PSI and about 3 GPM. The higher flow rinses faster, which suits soft washing and large flat areas. Note that its pressure is 2,500 PSI, not 3,000 as the model number might suggest.
What about cheap universal pumps?
Low-cost universal pumps from brands such as Himore sell for under $100. One 3,000 PSI Himore model with a 3/4 inch horizontal shaft is listed at about $83. We could not find a published flow rating or lifespan for it, so treat longevity as unknown. They can make sense for an old machine you use a few times a year.
What are the types of pressure washer pump?
- Wobble pumps: found on the cheapest machines. Published estimates put their life at roughly 200 to 400 hours, and they are sealed and not repairable.
- Axial cam pumps: used on most home gas washers. Estimates commonly run from 500 to 800 hours, though some sources quote less. Replacement is often cheaper than repair.
- Triplex plunger pumps: used on professional machines. Estimates start at about 2,000 to 3,000 hours between rebuilds, and they are designed to be serviced.
These figures come from pump retailers and industry guides, not from the manufacturers, so use them as a rough comparison. For more detail, read axial vs triplex pumps.
How do you match a replacement pump?
- Shaft direction: horizontal or vertical. A pump made for one will not work on the other.
- Shaft diameter: usually 3/4 inch on engines under 8 HP, 7/8 inch on many vertical engines and 1 inch on large engines such as the 13 HP class.
- Bolt pattern: measure the mounting holes on the engine flange.
- PSI and GPM: stay close to the original ratings. A widely used formula is engine HP = PSI x GPM / 1,100 for gas engines. A 3,000 PSI, 2.5 GPM pump needs about 6.8 HP.
- Connections: most pumps use a 3/4 inch garden hose inlet and an M22 or 3/8 inch outlet.
If the numbers do not match, the engine will bog down or the pump will underperform. Our guide to PSI vs GPM explains how the two ratings work together.
What makes pressure washer pumps fail?
CAT Pumps lists the main causes: cavitation from a restricted water supply or trapped air, running the pump dry, and heat build-up when the engine runs without the trigger pulled. A common recommendation is to shut the engine off for breaks longer than about a minute.
Oil matters too. AR recommends changing pump oil after the first 50 hours and then every 200 hours. CAT recommends its ISO 68 pump oil, changed after the first 50 hours and then every 500 hours. See what oil a pressure washer uses and how to winterize a pressure washer.
Should you repair or replace the pump?
Repair guides suggest replacing a pump when the repair would cost more than 40 to 50 percent of a new pump. For most axial pumps that means replacing. If a new pump costs close to the price of a new washer, compare the options in our guide to the best gas pressure washers first.
Frequently asked questions
How do I know which pump fits my pressure washer?
Check the shaft direction, shaft diameter and bolt pattern on your engine, then choose a pump with PSI and GPM close to the original.
How long does a pressure washer pump last?
Estimates vary by source. Axial cam pumps are commonly quoted at a few hundred hours, and triplex pumps at 2,000 hours or more between rebuilds.
Is it worth replacing a pressure washer pump?
Usually yes on a gas washer with a healthy engine. A replacement axial pump costs about $120 to $230, far less than a new machine.
Can I upgrade from an axial pump to a triplex pump?
Yes, if the shaft size and bolt pattern match and the engine has enough horsepower for the pump’s PSI and GPM.
Final verdict
For a typical home gas washer, the Simpson 90028 is the easiest and cheapest way back to full pressure. Owners of vertical-shaft machines should look at the AR RMW2.2G24-EZ, and anyone who cleans often should consider the CAT 4DNX27GSI triplex. Measure the shaft and check the ratings before you order, and change the oil on schedule so the new pump lasts.
