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Zenith® Guardian RO800
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Cleaner, better tasting water whenever you turn on the tap.
The Guardian RO800 is a compact reverse osmosis system that fits beneath your kitchen sink and delivers purified drinking water through its own brushed nickel faucet. There is no storage tank, so water is produced when you need it instead of sitting in reserve.
- 800 GPD membrane for strong everyday output
- 2:1 pure to drain ratio for more responsible water use
- Real time TDS display and individual filter life indicators
- Three cartridges with seven layers of filtration
- Alkaline and mineral postfilter returns the water to pH 7.5+
- Two year parts and labor warranty
- Free in-home testing
- Clear recommendations
- No pressure to buy
Smart performance without the bulky storage tank
No storage tank beneath your sink
The compact system produces purified water on demand. That frees up valuable cabinet space and avoids keeping treated water in a conventional storage tank.
Built for busy household routines
High capacity output supports drinking, cooking, coffee and everyday kitchen use without the slow refill pattern associated with many traditional systems.
See water quality and filter life at a glance
The integrated display shows treated water TDS and tracks F1, F2 and F3 separately. You can see which cartridge is approaching replacement instead of relying on guesswork.
Single twist cartridge changes with no tools
Each cartridge is designed for quick replacement. Zenith also offers scheduled professional maintenance, so the system can be inspected and verified at the same time.
A simple upgrade you can appreciate every day
From the first glass of water in the morning to dinner preparation at night, the Guardian RO800 gives your household a convenient source of purified water at the kitchen sink.
Fresh on demand
Purified water is produced when you use it rather than stored in a tank.
Better taste
Helps reduce substances that can affect the taste, odor and clarity of tap water.
Less bottled water
A reliable kitchen source can help reduce the need to keep buying bottled water.
Clear reminders
Individual filter indicators make routine maintenance easier to understand.
Designed to deliver more while wasting less
The Guardian produces two parts purified water for every one part sent to drain. A conventional under sink RO system commonly operates around one part purified water to four parts drain. That difference matters every time your household fills a glass, pot or coffee maker.
Performance depends on incoming water quality, pressure, temperature, usage, and proper maintenance. GPD is a membrane rating, and actual household production can vary.
Guardian RO800 system details
These specifications reflect the August 2026 product information and current published installation details.