Kirkland SignatureAlkaline Water

Disclosure grade D — No disclosure

This brand lists ingredients at most — no concentrations. You cannot compare what you cannot see; the blanks below are the point.

Character

Bands follow the water-sommelier convention (hardness = Ca×2.5 + Mg×4, as CaCO₃; “source protection” is the nitrate measure that world calls virginality) — computed from the values below, never asserted separately.

Where to order

Ways to get Kirkland Signature Alkaline Water

• Costco →Marketplace1 L x 18-count; Costco members only. Listing confirmed via search results.
• Instacart (Costco) →Grocery deliveryCostco via Instacart; no membership required but item prices are higher than warehouse.
• Costco Same-Day →Grocery deliveryCostco's same-day delivery (Instacart-powered); members sign in with Costco account.
• Costco search →MarketplaceCostco members; Kirkland Signature is Costco-exclusive.
• Amazon (resellers) →MarketplaceThird-party resellers only, typically marked up well above Costco price.

h2know doesn’t sell or ship water — we route you to sellers we’ve verified carry it (links checked 2026-09-11). Prices and availability change; none of these links affect our grades, rankings, or quiz results. Currently none are paid placements or affiliate links; if that ever changes we’ll disclose it right here.