How to Choose a Water Filter

Before buying anything, it's worth knowing what you're filtering for:

- If you're on a municipal water supply, your provider is required to publish an annual water quality report, often called a Consumer Confidence Report, which lists detected contaminants and their levels.

- If you're on a well, get your water tested by a certified lab, since well water quality varies enormously by location and isn't covered by municipal reporting.

- Common concerns worth checking for include chlorine taste and odor, lead (especially in older homes with older plumbing), hard water minerals, and in some regions, specific contaminants like nitrates or PFAS.

Buying a filter before knowing this is a bit like buying medicine before knowing the diagnosis — it might help, but you're guessing.

- Pitcher filters are the simplest entry point, good for improving taste and reducing chlorine, and reasonable for basic everyday drinking water needs in a small household.

- Faucet-mounted filters attach directly to your tap and filter water on demand, offering similar contaminant reduction to pitchers with less refilling but slightly slower flow.

- Under-sink filters are installed beneath the sink and connect to a dedicated tap, offering higher filtration capacity and often broader contaminant reduction, including some models rated for lead.

- Reverse osmosis systems, typically installed under the sink, filter out a wider range of contaminants including heavy metals, nitrates, and dissolved solids, at the cost of some water waste and a slower fill rate.

- Whole-house systems filter water as it enters your home, addressing issues like sediment or hardness across every tap, but are a bigger investment and typically don't target the finer contaminants that under-sink or reverse osmosis systems handle.

- Look for NSF/ANSI certification numbers specific to the contaminants you're trying to address — NSF/ANSI 53 covers health-related contaminants like lead, while NSF/ANSI 42 covers taste and odor improvements like chlorine.

- A filter can be certified for one thing and not another, so check the specific certification against your specific concern rather than assuming a general "certified" label covers everything.

- Filter cartridges need regular replacement, and the cost and frequency vary a lot between brands and filter types — factor this into the real cost of ownership, not just the upfront price.

- Reverse osmosis systems use more water per gallon filtered than other types, since a portion is flushed away as part of the filtration process.

- Under-sink and whole-house systems typically need professional installation, which adds to the upfront cost compared to a pitcher you can start using immediately.

- Single person or small household with basic taste/odor concerns: a pitcher or faucet filter is usually sufficient and easiest to maintain.

- Family with specific health-related contaminant concerns (lead, nitrates): an under-sink or reverse osmosis system rated for that specific contaminant is worth the investment.

- Whole-home hardness or sediment issues: a whole-house system addresses the problem at the source, though it's worth pairing with a targeted under-sink filter if you also have specific drinking water concerns.

Brand reputation matters less than the specific certification for your specific contaminant — a lesser-known brand with the right NSF certification will outperform a well-known brand without it. Similarly, more expensive doesn't automatically mean more effective for your particular water; it often just means more contaminants are covered, some of which may not apply to your situation at all.

If you're not sure where to start, a water test and a basic pitcher or faucet filter is a reasonable first step for most households. It buys you the information (what's actually in your water) and a modest improvement, and from there you can decide whether a bigger investment in an under-sink or whole-house system is actually warranted, rather than guessing upfront and potentially over- or under-buying.