Key Takeaways:

• Pre-filters (Annually): The sediment and carbon pre-filters should be changed every 12 months to protect the RO membrane.
• RO Membrane (2-3 Years): The core RO membrane typically lasts 2 to 3 years, depending on your water hardness and usage.
• Post-filter (Annually): The final carbon "polishing" filter should be changed every 12 months along with the pre-filters.
• Why it Matters: Neglecting filter changes can lead to foul-tasting water, damage to the system, and even allow contaminants to pass through.

A Reverse Osmosis (RO) system (with USA-made options available) is a fantastic investment in your family's health, but like any high-performance filter, it requires routine maintenance to keep it working correctly. Changing the filters on schedule is the single most important thing you can do to ensure you're getting pure, safe, and great-tasting water.

The Standard RO Filter Replacement Schedule

For most under-sink RO systems installed on DFW city water, the following schedule is recommended:

Once Every Year (12 Months):

• Stage 1: Sediment Pre-filter: This filter removes dirt, rust, and sand. It's the first line of defense and protects the more delicate filters that follow.
• Stage 2 & 3: Carbon Pre-filters: These filters remove chlorine and chloramines, which can destroy the RO membrane. They are absolutely critical for the system's longevity.
• Stage 5: Post-Carbon Filter: This is the "polishing" filter. After water leaves the storage tank, it passes through this filter one last time to remove any potential taste or odor.

Every 2 to 3 Years:

• Stage 4: The RO Membrane: This is the heart of the system. Its lifespan depends on the hardness of your water and how much water you use. In DFW, with our hard water, a 2-3 year replacement is typical. A key sign that the membrane is failing is if your water's TDS (Total Dissolved Solids) level starts to creep up.

What About Optional Stages?

• Alkaline/Remineralizing Filter (Annually): If you have an optional alkaline or remineralizing filter, it should be replaced every 12 months.
• UV Bulb (Annually): If your system has a UV light for disinfection (essential for well water), the bulb must be replaced every 12 months, even if it still lights up, as its UV output degrades over time.

What Happens If I Don't Change My Filters?

Skipping maintenance can lead to several problems:

1. Poor Taste & Odor: The carbon filters will become saturated and stop removing chlorine.
2. Membrane Damage: Chlorine exposure from depleted carbon filters will rapidly destroy the RO membrane.
3. Reduced Water Production: Clogged filters will slow down the system, and you'll get less water from the tap.
4. Contaminant Breakthrough: A failed membrane will no longer be able to remove dissolved solids, lead, PFAS, and other contaminants effectively.

Regular maintenance is simple, inexpensive, and ensures your RO system continues to provide the highest quality water for your family.

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Reviewed by Sai Akash Tumu, TCEQ Licensed Water Treatment Specialist (#WT0007448). Our approach is to educate first. For a personalized assessment, contact us for a free consultation.

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Disclaimer: This guide is for informational purposes only. Water conditions vary, and we recommend a professional on-site water test for an accurate solution. This is not medical advice. Read full disclaimer >