Annual Water Treatment Operating Costs
Updated February 20, 2026
The purchase price of a water treatment system is a one-time cost. The filters, salt, electricity, and maintenance are forever -- or at least as long as you run the system. A $200 RO system with $100/year in filters costs $1,400 over 12 years. A $1,500 softener with $120/year in salt costs $2,940. Here's the full operating cost picture for each system type.
Overview
The purchase price of a water treatment system is a one-time cost. The filters, salt, electricity, and maintenance are forever -- or at least as long as you run the system. A $200 RO system with $100/year in filters costs $1,400 over 12 years. A $1,500 softener with $120/year in salt costs $2,940. Here's the full operating cost picture for each system type.
Cost Breakdown
Pro Tips
- Buy replacement filters in annual packs -- most brands offer 15-25% savings over individual filter purchases.
- Set calendar reminders for filter changes. Running expired filters is worse than no filter at all.
- Track your salt usage. If it's higher than expected, the softener may be regenerating too frequently -- adjust the settings.
- Compare the annual operating cost of your system to buying bottled water. A family spending $30/month on bottled water pays $360/year -- more than most treatment systems.
Mistakes to Avoid
- Buying a cheap system with expensive proprietary filters that cost more annually than a premium system with standard filters.
- Running filters past their rated life to save money. Spent filters can release trapped contaminants and harbor bacteria.
- Not factoring in water waste for RO systems. The 3:1 or 4:1 waste ratio adds to your water bill.
- Forgetting to budget for annual UV bulb replacement. A UV system with an old bulb provides zero protection.
When to Call a Pro
Annual maintenance on whole-house systems (softener brine tank cleaning, media inspection) can be done by a water treatment service for $100-$200/visit. Most filter changes are straightforward DIY.
Bottom Line
Most water treatment systems cost $60-$200/year to operate. The under-sink RO + softener combo ($250/year total) provides the most comprehensive treatment for the lowest annual cost. Always compare operating costs, not just purchase prices.