Algae in Water
The short answer on algae
Household algae — the green film in water bottles, fridge reservoirs, and clear tanks — is a *light* problem, and the first fix is free: block the light and clean on a schedule. Lake blue-green algae (cyanobacteria blooms) is the other case — a public-event hazard whose toxins (microcystins) boiling does not remove; boiling can rupture cells and release more toxin. That boiling line is the single … The details — sources, official limits and honest removal methods — are in the complete guide: The complete algae guide.
How to remove algae — what actually works
| Technology | Where it lives | What to demand on paper |
|---|---|---|
| UV + + | Point-of-use or whole-house system per spec | Named NSF/ANSI protocol or third-party lab sheet for the exact model |
If a listing claims algae reduction and cannot name the standard or show the lab sheet, assume it does not have one. That single check filters out most of the market.
Can your refrigerator filter handle algae?
No — standard carbon cartridges are not engineered for it. The technologies above are the ones that address it; your fridge filter still does its own job (chlorine, taste, and with a 53 claim, lead and cysts). Fridge cartridges are built for chlorine, taste and odor (NSF/ANSI 42), plus lead and cysts on certified 53 tiers. If algae is your concern, keep the fridge cartridge for what it does well and put the right technology where you drink: see what your fridge model takes, then match the removal stage to the contaminant.
Algae questions, answered straight
Does boiling water remove algae?
Boiling is a concentration step, not a filter: water leaves as steam and whatever is dissolved stays behind, so levels rise by roughly the volume lost. The only heat-based method that works is distillation — capturing and condensing the steam. For algae specifically, see the full guide.
Is my refrigerator water filter enough for algae?
No — standard carbon cartridges are not engineered for it. The technologies above are the ones that address it; your fridge filter still does its own job (chlorine, taste, and with a 53 claim, lead and cysts). Match the technology to the contaminant, not the badge on the box.
How do I find out my actual algae level?
On city water, your utility's annual Consumer Confidence Report lists it free. On a well, a lab mail-in panel is the reliable route — the test-first card above links our guide to reading the results.
What removes algae from drinking water?
The technologies with a track record for algae: uv + +. Claims worth having come with a named standard (NSF/ANSI protocol or third-party lab sheet) — buy where the certificate names the exact part number.
Go deeper
Every contaminant, one page each
48 water problems from EPA primary, secondary and unregulated lists — sources, official limits, and which filters actually work (and which honestly don’t). Browse the Water Problems A–Z →