Waterway 817-0050 Filter Cartridge
Waterway OEM number • 40 sq ft • 6″ OD × 8.0625″ long
817-0050 is Waterway's number for this cartridge, not a part you have to buy from Waterway. The filter itself is a 40 square foot cartridge measuring 6 inches across and 8.0625 inches long, and Pleatco, Unicel, and Filbur all build it. If you read 817-0050 off an old cartridge or found it in your manual, any of the numbers below drops into the same housing.
Waterway also lists 03FIL1400, 25252, and 378902 against this cartridge. Different numbers on paper, same filter in the box.
Fitment notes
Semi-circular handle top with Pleatco's P3 adapter on the bottom, a 1-1/2 inch SAE thread. A Waterway single-port front access skimmer takes one of these, a double-port takes two side by side. Both cross-reference sheets also file this cartridge under Bullfrog Spas, and Unicel lists it for Custom Molded Products front access skimmers as well. Three square-foot ratings circulate for it and all three are real: Pleatco rates the media at 40, Unicel rates its 6CH-940 at 45, and Unicel's application tables call it a 50 sq ft cartridge, which is the housing rating the part number is named for. The 40 recorded here is Pleatco's own figure for its own part.
What to buy instead
Replacements for the Waterway 817-0050
Each button searches Amazon for one of the numbers this cartridge is sold under. The OEM version is usually the most expensive of the set and the aftermarket versions are the same physical filter, so it is worth checking all of them before you order.
Every number for this filter
| Brand | Part Number | Type |
|---|---|---|
| Waterway | 817-0050 | The number you searched |
| Pleatco | PWW50P3 | Aftermarket equivalent |
| Unicel | 6CH-940 | Aftermarket equivalent |
| Filbur | FC-0359 | Aftermarket equivalent |
| Master Spas | X268549 | Other OEM number |
| Waterway | 03FIL1400 | Other OEM number |
| Waterway | 25252 | Other OEM number |
| Waterway | 378902 | Other OEM number |
Full specs, the cartridge diagram, and the complete compatibility list live on the PWW50P3 cartridge page. You can also see every 6″ × 8.0625″ cartridge if you are checking a measurement rather than a part number.
Equipment that uses this cartridge
Looking for a different model? Browse every Waterway model we cover.
Frequently Asked Questions
What filter replaces the Waterway 817-0050?
The PWW50P3 replaces it directly, and so does every cross-reference for it: 6CH-940, FC-0359. All of them are the same 40 sq ft cartridge at 6" outer diameter and 8.0625" long. Buy whichever is cheapest at the time with solid recent reviews. The same cartridge also shows up as Master Spas X268549, Waterway 03FIL1400, Waterway 25252, Waterway 378902, so those are not different filters either.
Is the Waterway 817-0050 the same as the PWW50P3?
Yes, physically the same filter. Waterway 817-0050 is an OEM number, meaning it is the code Waterway put on the cartridge that shipped with the equipment. Waterway does not manufacture cartridges. Pleatco, Unicel, and Filbur do, and they sell the identical part under their own numbers at a lower price. Match the dimensions against your old cartridge before ordering and you are covered.
Do I have to buy the Waterway version?
No. Nothing about the housing requires an OEM-branded cartridge, and the warranty on your equipment is not voided by using an aftermarket filter that meets the same spec. The reason to buy OEM is convenience, not performance. The reason not to is price, which is often a meaningful gap for an identical part. What matters is that outer diameter, length, and end-cap style all match.
What size is the Waterway 817-0050?
6 inches in outer diameter, 8.0625 inches long, with 40 square feet of filter media. Both measurements need to land within about an eighth of an inch, and the end caps have to match so the cartridge seats correctly when you close the lid. Measure your old one rather than trusting a number that has worn off the label.
Last verified September 2026