Quick Answer: Costco sells water filters outright in only two forms: Kirkland Signature/Brita pitcher cartridges and four boxed reverse-osmosis systems (Brondell Circle about $290, Delta Clarifi 6-Stage about $800, Pure Blue 1:1, and an iSpring alkaline RO unit) — a much narrower lineup than Amazon’s dozens of RO, under-sink, and whole-house options. Its “EcoWater” whole-house listing isn’t a product purchase at all: it books a free in-home consultation with a local dealer, and documented owner quotes for the system itself run $3,600 to $10,000 installed. Costco.com lets non-members buy online for a 5% surcharge, so a membership isn’t strictly required unless you’ll be back for replacement cartridges.
Costco shows up constantly in “where should I buy this” searches because shoppers assume warehouse pricing beats everything else by default. For water filters, that’s only true for part of the lineup — the packaged RO systems are genuinely well-priced, but the whole-house category isn’t sold the way the rest of the site implies.
Costco water filters by the numbers
- 5% non-member surcharge applies to every Costco.com order if you don’t hold a Gold Star membership ($65/year) — confirmed on Costco’s own customer-service page, with prescription drugs as the only exemption.
- The Brondell Circle RO system sells for about $289.99 at Costco (listed against a roughly $370 regular price), while the Delta Clarifi 6-Stage RO runs about $799.99 and claims reduction of 90-plus contaminants in about 60% less under-sink space than a tank system.
- EcoWater whole-house system quotes documented by owners run $3,600 to $10,000 installed, with some buyers reporting $4,000-plus for what other reviewers call a basic setup — well above typical whole-house-system pricing elsewhere on this site (SpringWell CF1 whole-house, for comparison, runs about $1,040).
- Costco’s return policy carries no stated time limit on most merchandise, with electronics as the main 90-day exception — broader than Amazon’s standard 30-day return window.
What’s actually for sale at Costco
| Product | Type | Price | How you buy it |
|---|---|---|---|
| Kirkland Signature filter cartridges | Pitcher cartridge (Brita-compatible) | 10-pack, budget-priced | Off-the-shelf, in warehouse or online |
| Brita Advanced Filters | Pitcher cartridge | 8- or 10-pack | Off-the-shelf, in warehouse or online |
| Brondell Circle RO | Under-sink reverse osmosis | ~$290 | Off-the-shelf, boxed, self-install |
| Delta Clarifi 6-Stage RO | Under-sink reverse osmosis | ~$800 | Off-the-shelf, boxed, self-install |
| Pure Blue 1:1 RO | Under-sink reverse osmosis | Varies by listing | Off-the-shelf, boxed, self-install |
| iSpring 6-stage alkaline RO | Under-sink reverse osmosis | Varies by listing | Off-the-shelf, boxed, self-install |
| EcoWater whole-house systems | Whole-house filtration/softening | $3,600-$10,000 (quoted) | Consultation booking only — local dealer, professional install |
The EcoWater listing isn’t what it looks like
This is the part of Costco’s water-filter page most shoppers miss. Every other item in the table above is a normal e-commerce listing: pick it, pay for it, it ships or you carry it out of the warehouse. The EcoWater listing works differently — clicking through starts a free in-home consultation with a local EcoWater dealer, water test included, and no price is shown until after that visit. Buyers who’ve documented their quotes report figures from $3,600 up to $10,000 installed, and EcoWater’s own review scores (2.6/5 on Yelp, 2.9/5 on Trustpilot) skew toward complaints about being quoted more than expected for a basic setup. None of that makes EcoWater a bad system, but it does mean the “Costco price” you’d assume from browsing the site simply doesn’t exist for whole-house treatment — get an independent second quote before you commit to the consultation.
For a fixed, published price on whole-house filtration instead, see our best whole-house water filter guide, which ranks systems like the SpringWell CF1 that list an actual price up front.
Do you actually need the membership?
For the boxed RO systems and cartridges, no — not strictly. Costco.com sells to non-members at a 5% surcharge over the member price, so on a $290 Brondell Circle that’s roughly $14.50 extra, and on the $800 Delta Clarifi it’s about $40. If that’s your only Costco purchase, the surcharge is usually cheaper than a $65/year Gold Star membership. Where membership starts to pay off is repeat buying — Kirkland and Brita cartridge multi-packs are a recurring purchase, and Executive members also earn 2% cashback on top.
1. APEC ROES-50 — Best Value RO, No Membership Needed
APEC ROES-50 Reverse Osmosis System
If Costco's four-item RO lineup doesn't include the system you actually want, APEC's ROES-50 is the proven budget benchmark this site ranks as best value in our full reverse-osmosis roundup — a 5-stage under-sink tank system, WQA-tested, made in the USA. It's priced close to the Brondell Circle without needing a Costco account or a warehouse trip.
Check price on Amazon →Replacement filters on time, every time — Prime ships them free in two days. Try it free for 30 days so the next cartridge is already on the way before the current one’s rated gallons run out.
2. iSpring RCC7AK — Best for Remineralized Taste
iSpring RCC7AK Reverse Osmosis System
Costco's iSpring listing is a 6-stage alkaline RO unit too, but availability and bundled accessories vary by warehouse and season. The RCC7AK is the equivalent model this site tracks at a stable, published price, adding minerals back after the RO membrane strips them out — closer to what the Delta Clarifi promises, at roughly a third of the cost.
Check price on Amazon →Full brand lineup in our iSpring water filter review.
3. Waterdrop G3P800 — Best Tankless, Closest to Delta Clarifi’s Space Savings
Waterdrop G3P800 Tankless Reverse Osmosis
Delta Clarifi's pitch at Costco is roughly 60% less under-sink space than a tank system — the Waterdrop G3P800 delivers the same tankless space savings, at a published everyday price instead of a warehouse markdown that can change month to month. Its smart faucet shows real-time TDS, useful for confirming the membrane is still performing without a separate meter.
Check price on Amazon →For the full field of tankless options, see our best tankless reverse osmosis system guide.
How to choose: Costco vs. Amazon vs. a dealer quote
- Buying cartridges or a boxed RO system you already know you want? Costco’s four RO listings and Kirkland/Brita cartridges are competitively priced, and the open-ended return policy is genuinely better than most online retailers’.
- Want a specific brand, GPM rating, or certification Costco doesn’t stock? Amazon’s selection is far wider, and Prime shipping usually beats a warehouse trip for a bulky box.
- Considering whole-house filtration or softening? Treat the EcoWater listing as a lead into a sales consultation, not a price. Get at least one independent quote — from a published-price option like SpringWell, or a local plumber — before the in-home visit.
- Not a member and only buying once? The 5% non-member Costco.com surcharge is usually cheaper than a $65/year membership for a single purchase.
The bottom line
Costco’s water-filter selection is real but narrow: Kirkland/Brita cartridges and four boxed RO systems are honestly priced and covered by an unusually generous return policy, but the “EcoWater” whole-house listing is a consultation funnel with quotes running $3,600 to $10,000 and mixed reviews — not a fixed warehouse price. Shoppers who want more brand choice, a specific GPD rating, or just don’t want to book an in-home sales visit are generally better served by a published-price option like the APEC ROES-50, iSpring RCC7AK, or Waterdrop G3P800, all shippable via Amazon Prime without a membership. For whole-house filtration specifically, compare real published prices in our best whole-house water filter guide before sitting through any consultation.
Prices are approximate and change often — tap any button above to check the current Amazon price.