You’re on a job and your jetter suddenly won’t build consistent pressure. The engine sounds fine, water-tank's full, the nozzle’s right, but pressure's not building ... or you've got nothing. Sound familiar?

More often than not, that problem starts upstream, before water ever hits the pump. One of the easiest yet most overlooked jetter-maintenance steps is cleaning its inlet-water strainer, aka the jetter's Water Filter. It’s a small and simple part, but it protects the most expensive component on your jetter - the high-pressure pump!

In this breakdown, we’ll cover what the water filter actually does, why it matters more than most operators think, and how to clean it the right way. Let’s break it down and keep your pump drinking clean water.

What Does a Jetter’s Water Filter or Strainer Do?

The water filter, or strainer, is your jetter’s first line of defense. Its job is simple: catch debris before it enters the pump. Whether your jetter is tank-fed or hooked to a garden hose, water can carry grit, rust flakes, organic debris, or sediment. The strainer traps that junk before it gets pulled into the pump’s valves and plungers.

Think of it this way. If your pump’s drinking dirty water, it’s like feeding bad fuel into an engine. It might run for a while, but damage is already happening.

PRO TIP: Always clean the filter before a job, not after a problem shows up. Prevention beats repairs every time.

Why Cleaning Your Water Filter or Strainer Matters

When a strainer starts to clog, water flow into the pump is restricted. That leads to a chain reaction of problems:

• Reduced flow means low pressure at the nozzle

• Restricted flow can cause pump cavitation, destructive water vaporization inside the pump

• Cavitation is the biggest enemy of your jetter's pumping-system, as hundreds of shock-waves thrash on the pump's internals every minute, as well as items connected to the pump such as drive-components and the engine-shaft itself.

Water is your tool. Starve the pump, and you’re asking it to destroy itself. We’ve seen pumps wiped out because of something that could have been prevented with a five-minute cleaning. A five-dollar maintenance habit can save you from a five-hundred-dollar repair and days of downtime.

How Often Should You Clean It?

The short answer is daily. As Jonesie likes to say, “Daily, but even once a week is better than nothing.” 

If you’re jetting every day, using questionable water sources, or running off a tank that sits between jobs, daily checks matter even more. Algae, slime, and sediment build fast. And it's not just gradual buildup - often something falls into the water-tank that causes an immediate problem: gloves, lunch wrappers, rags - a recent customer found a rogue golf-ball from a nearby range! Making strainer-cleaning part of your end-of-day routine, right alongside oil checks and hose inspections can prevent catastrophic failure. And when it’s a habit, it doesn’t get skipped.

How to Clean a Jetter Strainer

This is a simple job, but doing it right matters. Here’s the process we recommend.

Step-1: Remove and Inspect the Bowl

Most strainer bowls twist off by hand, though some may need a wrench. Even clear bowls can hide algae or biofilm, so don’t rely on looks alone. Take a moment to look for cracks - especially due to freezing in winter. Pay attention to the gasket or o-ring and don’t damage it - or lose it - during removal.

Step-2: Inspect and Clean the Screen

Pull out the screen and rinse it thoroughly with clean water. If it’s been sitting for a while, check the water tank too. Organic debris like leaves, pine-needles, slime and algae often start there and end up in the filter.

Step-3: Scrub if Needed

If rinsing isn’t enough, use a small brush or an old toothbrush. Look for fine sediment, sand, pine needles, or organic buildup that can block flow even when it looks minor.

Step-4: Inspect and Clean the Gasket and Housing

Wipe out the housing and clean the sealing surfaces. Take a moment to look for cracks - especially in winter months. Dirt on the gasket or o-ring can cause air leaks, which kill prime fast. Inspect the gasket for cracks or wear and replace it if needed.

Step-5: Reassemble Properly

Reinstall the screen squarely and thread the bowl back on evenly. Snug it down, but don’t overtighten. Many operators like Banjo strainers because the framed screen makes reassembly easier and more consistent.

PRO TIP: Keep a spare gasket or o-ring in the truck. It’s cheap insurance.

If Your Pump Won’t Prime

Most Jetters Northwest units are self-priming, but a dry or air-locked strainer can slow things down. If the pump won’t prime, add water to the tank and give the system a moment to purge air before sealing everything back up. Let the pump pull solid water before you put it under load.

Real-World Example: The Cost of Water-Filter Neglect

A jetter with serious pump damage recently came into the shop. The cause? Its filter-strainer was packed solid with leaves. The filter did its job, but the operator never checked it. Sadly, that restriction led to cavitation-damage that trashed the jetter's high-pressure pump - a very expensive repair bill that was totally avoidable via easy, routine maintenance. The takeaway is simple: Maintenance equals uptime. Neglect turns into expensive lessons.

Keep It Clean, Keep It Jetting

Cleaning your jetter's water filter typically takes only a minute or two, costs almost nothing, and protects the heart of your jetter; its high-pressure pump.  Water is your hydro-jetter's tool, and a clean filter allows it to flow freely to the pump. So make cleaning it part of your daily routine - as well as the inside of your water-tank - and your pump will reward you with years of reliable service. Treat it right, keep it clean, and your pump will reward you with years of reliable service.

If you need replacement strainers, gaskets, or other jetter essentials, visit our online store or reach out to our team. We’re always happy to help you get set up right.

JETTERS NORTHWEST is a 20+ year-old product line of Seattle Pump & Equipment Co., a service and sales center for jetters for over 50 years.