MadMax Trade Supply
Carbon, white and sediment water filter cartridges with a metal housing on a kitchen counter.

Under-Sink, RO & Whole-House Filters

Replacement cartridges and membranes for under-sink, reverse-osmosis, pitcher and whole-house systems, matched by the system model or the cartridge size printed on your current filter. We do not sell water-softener salt. Brand or model names are for compatibility only.

Available to order

Prices include sales tax (see terms). Items marked "Shipping calculated before payment link" have shipping calculated and shown in your payment link before you pay. Typical delivery is a few business days in the contiguous United States. A delivery estimate is confirmed in your payment-link email. Shipping to Alaska, Hawaii, Puerto Rico, other US territories and APO/FPO addresses is not included in any price; we quote it in your payment-link email before you pay. Images are representative; tap a picture to enlarge it.

Don't see your exact item? Email us the part number or size: tamara@madmaxsupply.com

Attributes we list for each item: Filter type, System or pitcher model, Cartridge size, Stage (if a set).

Fix-it guides

Buying guides

Part-number replacements

FAQ

How do I find the right cartridge?

Read the model on the filter housing or the part number on the current cartridge. Email it to us if you are unsure.

Do you sell softening salt or resin?

Softener salt is not offered (it ships on pallets). We quote drinking-water and whole-house cartridges and RO membranes. If you need a softener part, send the system model and we will tell you whether we can source it.

How often should cartridges be changed?

Follow your system maker's schedule. Many under-sink carbon filters are changed every 6 months; RO membranes last longer. Water quality and use affect the interval.