Replacement filters & cartridges
Replacement Water Filters & Cartridges
A filter only protects you while its cartridge is fresh. Replacement is the recurring cost of every system, so it's worth knowing how to match the right part, how often each type needs changing, and how to buy without getting the wrong or a counterfeit refill.
Disclosure: BotledWater may earn a commission from qualifying purchases made through links on this page. This does not affect our editorial standards or product comparisons. See our Affiliate Disclosure for details.
Quick picks
We are still verifying product picks for drinking-water filters, and we only list products after an editor has checked them. Until then, here is how to build a shortlist that fits your home.
- Independent certification. Look for NSF/ANSI certification for the contaminants you care about: 42 covers taste and odor, 53 health-related contaminants such as lead, 58 reverse osmosis, 401 emerging compounds. A marketing claim is not a certification.
- Your water report. Check your utility's annual water quality report or run a lab test first, so you buy for the contaminants you actually have.
- Rated capacity and cost. Divide the cartridge price by its rated gallons to compare true running costs across models.
- Flow and fit. Check the flow rate and whether it fits your sink, counter or fridge shelf.
Full comparison
Our product comparison for drinking-water filters fills in as products are reviewed. These are the criteria we compare on, so you can check any model against them yourself.
| What to compare | What to look for |
|---|---|
| Independent certification | Look for NSF/ANSI certification for the contaminants you care about: 42 covers taste and odor, 53 health-related contaminants such as lead, 58 reverse osmosis, 401 emerging compounds. A marketing claim is not a certification. |
| Your water report | Check your utility's annual water quality report or run a lab test first, so you buy for the contaminants you actually have. |
| Rated capacity and cost | Divide the cartridge price by its rated gallons to compare true running costs across models. |
| Flow and fit | Check the flow rate and whether it fits your sink, counter or fridge shelf. |
| Installation | Countertop and pitcher filters need no plumbing. Under-sink systems connect to the cold-water line and usually add a faucet. |
1. Identify the exact part
- Find the model or part number printed on the old cartridge, the filter housing, or the system's manual — not just the brand.
- For refrigerators, use the fridge's model number (usually inside the door or wall) to look up the compatible filter.
- For under-sink and whole-house housings, note the cartridge size (for example 10-inch or 20-inch, standard or big-blue) as well as micron rating.
2. Typical replacement schedule by system
- Pitcher and dispenser filters: follow the rated gallons or months — commonly a couple of months for standard carbon filters.
- Refrigerator filters: commonly about every six months, or sooner if flow drops.
- Under-sink carbon and RO pre-/post-filters: commonly every 6–12 months.
- RO membranes: often two to three years under normal use, depending on water quality and volume.
- Whole-house sediment and carbon cartridges: range from a few months to a year or more with usage and incoming water quality.
- Shower and pet-fountain filters: typically a matter of weeks to a few months — check the product's rating.
3. Buy the right refill, safely
Manufacturer (OEM) filters carry the certifications the system was tested with. Third-party "compatible" filters can be fine, but confirm they list their own independent certification rather than borrowing the brand's — a compatible fit is not the same as a certified performance claim.
Counterfeit filters exist for popular models. Buy from the brand's own storefront or an authorized seller, check packaging and part numbers match, and be wary of prices far below normal.
4. Don't forget maintenance parts
Systems with membranes, UV lamps, O-rings and housing wrenches have their own replacement parts. Swapping the O-ring when you change a cartridge helps prevent leaks, and UV lamps are typically replaced on a fixed annual schedule regardless of appearance — follow your model's manual.
Frequently asked questions
What happens if I don't change my filter on time?
A spent filter stops reducing what it was designed to reduce and can restrict flow. Carbon filters that are overused may also stop working while still letting water through, so a normal flow rate does not prove the filter is still effective.
Can I use a different brand's replacement filter?
Sometimes, if it's designed for the same housing, but performance and certification differ. Check that the replacement carries its own independent certification for the contaminants you care about.
How do I remember when to replace it?
Note the install date on the housing or set a calendar reminder. Some systems include a change indicator, but a calendar reminder works for every type.
Related guides & comparisons
What should you do next?
Continue with the most relevant guides, comparisons and data for this topic.
