What are expert tips for filter replacement schedules?

Set calendar reminders for each filter. Most people forget because the system works silently. Buy filters in bulk packs -- they're significantly cheaper per unit and you'll always have one on hand. Write the installation date on each new filter with a permanent marker. If you're on a well, test your water annually and adjust filter schedules based on results. Seasonal water quality changes affect filter life.

What mistakes should I avoid with filter replacement schedules?

Running filters past their rated life -- a saturated carbon filter can dump contaminants back into the water. Only changing the filters you can see (sediment pre-filter) and neglecting the carbon and RO membrane. Buying the cheapest generic replacement filters. Quality varies enormously -- stick with OEM or certified aftermarket. Assuming the water tastes fine means the filter is still working. Many contaminants have no taste or odor.

Filter Replacement Schedules

Maintenance Guide Easy 10-30 minutes per filter change $10-$80 per filter depending on type

Created by Ryan Pietrzak Illinois Licensed Plumber · In the plumbing industry since 2009

Updated February 20, 2026

Key Takeaway

Every water filter has a lifespan, and using one past its prime is worse than you think. A spent filter doesn't just stop working -- it can release trapped contaminants back into your water and become a breeding ground for bacteria. The replacement schedule depends on the filter type, your water quality, and how much water you use. Here's a practical guide to when each type needs swapping.

Overview

What to Know

Sediment Pre-Filters

Replace every 3-6 months. These are the first line of defense, catching sand, rust, and particles. They clog visibly -- you'll see the white filter turn brown or orange. In high-sediment water (wells, older municipal systems), you may need to change them monthly. They're cheap ($5-$10) so there's no reason to stretch them.

Carbon Block / Activated Carbon

Replace every 6-12 months or per the manufacturer's gallon rating. Carbon filters remove chlorine, taste, odor, and many organic chemicals. Unlike sediment filters, you can't see when they're spent -- they stop absorbing contaminants long before they stop flowing. Follow the gallon rating or time interval, whichever comes first.

Reverse Osmosis Membranes

Replace every 2-3 years. The RO membrane is the most expensive filter in the system ($30-$80) but also the longest-lasting. Signs it needs replacement: decreased water production, TDS readings climbing back up, or the system running much longer to fill the tank. Pre-filters protect the membrane -- if you skip pre-filter changes, the membrane fails faster.

Whole-House Systems

Whole-house carbon filters: every 3-6 months for cartridge types, every 5-10 years for tank-based backwashing systems. Whole-house sediment filters: every 1-3 months depending on water quality. UV bulbs: replace annually regardless of whether they still light up -- UV output degrades before the bulb burns out.

Pro Tips

Set calendar reminders for each filter. Most people forget because the system works silently.
Buy filters in bulk packs -- they're significantly cheaper per unit and you'll always have one on hand.
Write the installation date on each new filter with a permanent marker.
If you're on a well, test your water annually and adjust filter schedules based on results. Seasonal water quality changes affect filter life.

Mistakes to Avoid

Running filters past their rated life -- a saturated carbon filter can dump contaminants back into the water.
Only changing the filters you can see (sediment pre-filter) and neglecting the carbon and RO membrane.
Buying the cheapest generic replacement filters. Quality varies enormously -- stick with OEM or certified aftermarket.
Assuming the water tastes fine means the filter is still working. Many contaminants have no taste or odor.

When to Call a Pro

If your water quality changes suddenly (new taste, color, or odor) despite fresh filters, the source water may have changed. Have it tested. If your RO system's production drops significantly even with a new membrane, the system pressure or tank bladder may be the issue.

Bottom Line

Sediment filters every 3-6 months, carbon every 6-12 months, RO membranes every 2-3 years, UV bulbs annually. Mark the dates, buy in bulk, and don't stretch filter life. A $20 filter change protects thousands of dollars of plumbing and your family's health.