ZMFIL Green Cap Water Filters

Grit kills pumps quietly. One piece of pipe scale through a check valve and you are buying a repair kit instead of finishing the job. The General Pump ZMFIL green cap water filter screens your supply water before it reaches the pump, and this page covers the complete filter plus every replacement part. Questions? Call 301-519-9274 and ask for the parts counter.

Why a Green Cap Filter Belongs on Your Inlet

The ZMFIL is an inline inlet filter that threads in between your water supply and the pump, 1/2 inch FPT in and 1/2 inch MPT out. Inside the anodized aluminum body, a stainless steel mesh screen catches sand, rust flakes, and pipe scale before they reach your packings and valves. It is rated for 145 PSI and water up to 176 degrees, so it lives on the supply side only, never after the pump. The green cap spins off by hand, no tools, which is the whole point. A filter you can rinse in thirty seconds is a filter that actually gets cleaned.

Make the cleaning a habit. Pull the screen at the end of each work week, or right away any time the machine starts surging, since a starved inlet mimics a bad unloader. The screen and the Buna N O-ring under the cap are the two wear items. A torn O-ring shows up as a drip or as air getting sucked into the pump, and at under two dollars it is the cheapest fix in pressure washing. Cracked cap from a freeze or a drop? Replace just the cap and keep the body.

Filter and Every Replacement Part

Buy a spare screen and a couple of O-rings with the filter. They weigh nothing and they save a supply run mid-season.

Related Collections

• All water filters and inline filters
• General Pump water filter parts
• Hypro filters and strainers
• Garden hose pump inlets with filters
• General Pump parts and pressure washer pumps
• Local pickup at our Gaithersburg store

Frequently Asked Questions

What does a ZMFIL green cap filter actually protect?

Your pump's check valves and packings. Sand and scale in supply water score the valve seats and chew up seals, and that damage shows up as pulsing or lost pressure. A screened inlet is the cheapest pump insurance you can buy.

How often should the screen get cleaned?

Weekly on a working rig, or immediately if pressure starts surging. The cap comes off by hand, the screen rinses clean under a tap, and you are back to work in under a minute.

My green cap filter is leaking. Which part do I need?

Start with the O-ring, since the Buna N seal under the cap flattens and tears with age. If the cap itself is cracked, usually from freezing over the winter, the replacement cap threads onto your existing body.

Will the ZMFIL handle a big machine?

It is rated around 5.8 GPM and 145 PSI, which fits most 4 GPM rigs with room to spare. Running 8 GPM machines should step up to a larger canister style unit from our water filter collection so the inlet never starves.