We are often asked, “Does my fridge filter really do anything?” The short answer is yes. Fridge filters vary greatly between brands and models, but the vast majority use Granular Activated Carbon (GAC) to remove chlorine, organic matter, and some odors and gases. GAC is a catch-all of sorts, so it may or may not remove other contaminants it isn’t specifically designed for — depending on whether those contaminants are bound to organic matter or particulates that stick to carbon.
When Should I Change It? Is the Service Light Accurate?
It depends on the filter and the incoming water quality. A common misconception is that the fridge alarm measures water quality and knows when the filter stops working. In reality it’s just a flow meter that tells you to replace the filter every 100 gallons or so, regardless of what’s coming in.
Fridge filters stop filtering long before they ever plug up, because they rely on adsorbing chlorine to improve taste rather than physically removing particulates. That said, the alarm is set well below the filter’s actual capacity — you’re generally fine to about 125% of the rated gallons. The exception is the models with very small filters. Cut some of them open and you’ll find maybe a tablespoon and a half of carbon, in which case the 100-gallon rating is probably accurate.
What Fridge Filters Are Designed For
Fridge filters are designed for the majority of municipal water sources regulated under the Safe Drinking Water Act and monitored regularly for low-level contaminants. Their intent is to remove the chlorine municipalities use to disinfect supplies. Chlorine gives water an off taste and smell, and creates disinfection byproducts (DBPs) when it reacts with organic matter. DBPs are a genuine health concern and some are known carcinogens. Fridge filters typically do a mediocre job of removing them.
When a Fridge Filter Isn’t Enough
There are two common situations where we upgrade someone’s drinking water beyond the fridge filter.
1. The filter isn’t sufficient for the incoming water quality
There are plenty of water sources where a fridge filter is entirely sufficient. If you just need to knock down some chlorine and get better-tasting water, it’s a great option.
But we encounter water in Northern Nevada well beyond what a fridge filter can handle. Some local supplies run close to regulatory limits for disinfection byproducts, and contaminants don’t become safe simply because they sit a few parts per billion under a legal threshold — and that level of DBPs will pass straight through most fridge filters. Some smaller systems in the region have historically struggled with arsenic, lead, and coliform.
Private wells often test high in heavy metals, nitrates, and other contaminants a fridge filter won’t touch. Always test a private well through a certified lab before drinking the water.
2. Your standards are higher than the EPA’s
If you offer most people a glass of water containing uranium and one without, they’ll take the one without — regardless of the level. The EPA’s limits are the point at which a contaminant becomes legally actionable, not the point at which it becomes desirable. Plenty of people would rather their drinking water simply not contain something, whatever the number says.
That’s a reasonable standard to hold, and it’s the reason many households install filtration well beyond what their refrigerator provides.
See our whole home water filtration systems for Northern Nevada.