What Happens If You Don’t Change Your Water Filters?

It’s easy to forget about the things we don’t see—especially when they’re tucked away under a sink, in a basement, or outside the house. But when it comes to your water filtration system, neglecting regular filter maintenance can have serious consequences for your water quality, plumbing, appliances, and even your health. So what actually happens if you go six months... or a year... without changing your filters?

Let’s take a month-by-month look at what happens when your filters are left untouched—and why staying on schedule matters more than you might think.

Month 1–3: Everything Looks Fine (But Trouble Is Brewing)

For the first couple of months after your recommended filter replacement date, you probably won’t notice any immediate issues. Water may still look and taste okay, especially if you're using a multi-stage system. But behind the scenes, your filters are gradually becoming clogged with sediment, bacteria, and chemical residues. The longer you wait, the harder your system has to work.

What’s happening:

• Sediment and carbon filters are beginning to saturate

• UV systems may lose lamp intensity

• RO membranes may already be under increased pressure

Month 4–6: Reduced Flow and Performance Drops

As filters clog further, water pressure may begin to drop throughout your home. Showerheads might not deliver as much force, faucets may trickle, and your appliances—especially those that depend on clean water like ice makers, dishwashers, or washing machines—can start working less efficiently or clog entirely.

What you might notice:

• Slower water flow at taps

• Water starts tasting or smelling slightly off

• Appliances may show early signs of scaling or residue

Month 7–9: Contaminants Start Sneaking Through

By now, your filters are likely overloaded. In activated carbon filters, once the adsorption sites are saturated, contaminants like chlorine, VOCs, or disinfection byproducts (THMs) may pass right through into your drinking water. If you have a UV system and haven’t replaced the lamp, its effectiveness against bacteria and viruses may be significantly reduced—even if the light is still on.

Health risks may include:

• Exposure to chlorine, lead, pesticides, or bacteria

• Increased risk for sensitive individuals (children, elderly, immunocompromised)

Month 10–12: System Damage and Water Quality Degrades

At this point, your filters are doing more harm than good. Sediment filters may begin to break down, releasing trapped material back into your water. RO systems can experience membrane fouling, leading to expensive repairs. In some cases, bacterial growth can occur inside the system—turning your filter into a breeding ground.

You may experience:

• Foul odors, cloudiness, or visible particles in water

• Potential health concerns due to microbial growth

• Costly system damage or the need for premature replacement

Long-Term Consequences of Filter Neglect

• Shorter system lifespan – Overworked components wear out faster

• Wasted energy and water – Particularly for reverse osmosis systems with clogged membranes

• Increased repair costs – From clogged plumbing to damaged appliances

• Compromised health – Especially with bacteria and heavy metal exposure

Why Filter Maintenance Isn’t Optional

Think of your water filter like the oil in your car. You wouldn’t go a year without an oil change—so why risk your health and home by skipping filter replacements?

Depending on your system, filters should be replaced every:

• 6 months for sediment and carbon filters

• 12 months for UV lamps

• 2–3 years for RO membranes (if properly maintained)

Your manufacturer’s guidelines—and your water quality—will ultimately determine the ideal schedule.

 Don’t Wait Until It’s Too Late

Delaying filter changes may save you a few bucks in the short term, but the long-term costs to your health, home, and wallet can be significant. If you’re unsure when your last filter change was, now is the time to check.