Start with the full cabinet, not an empty rectangle
Brondell lists the RC100 enclosure at 13.8 inches long, 9.25 inches wide, and 16.5 inches high. That footprint must share the cabinet with the trap, disposal, shutoff valve, supply line, drain line, hinges, and anything you still plan to store.
Use a cardboard box or painter's tape to represent the enclosure. Then open and close the cabinet, reach the shutoff, and trace gentle tubing routes. Leave working room for filter changes instead of treating every free inch as usable storage.
| Connection or space | What to confirm |
|---|---|
| 13.8 × 9.25 × 16.5 inch enclosure | Fits with service and tubing clearance |
| Cold-water supply | Valve and adapter condition match the manual |
| Drain | A permitted drain-saddle location is accessible |
| Dedicated faucet | An existing opening works or the sink can be drilled safely |
| No outlet needed | Electrical access is not required for normal operation |
The enclosure does not make installation plumbing-free
The Circle hides its filters and reservoir, but it still connects to the cold-water supply, sends reject water to the drain, and dispenses through a dedicated faucet. Those are the same three planning points that make many RO installations more involved than direct carbon filtration.
A careful homeowner may be comfortable when the valve, drain, and existing faucet opening match the current manual. Hire a qualified plumber when the drain is crowded, the valve is corroded, a new hole must be drilled in stone or porcelain, or local rules require professional work.
- Photograph the cabinet before ordering
- Keep the shutoff accessible
- Do not connect the system to hot water
- Follow the current flushing and leak-check instructions
- Recheck every fitting after the cabinet has remained pressurized
RF-20 and RF-40 do different jobs
The RF-20 set includes the sediment, pre-carbon, and post-carbon stages and follows a six-month schedule. The RF-40 is the reverse-osmosis membrane and Brondell lists a 24-month schedule. Changing RF-20 does not automatically mean RF-40 is due.
Keep both part numbers with the installation date. Water quality, use, flow changes, and the current manual can call for earlier attention. Buying by color or housing shape is risky because similar-looking cartridges can have different connections or media.
| Replacement | Published schedule | Planning habit |
|---|---|---|
| RF-20 set | Every 6 months | Use a recurring six-month reminder |
| RF-40 membrane | Every 24 months | Track separately from the RF-20 changes |
| System sanitation and leak inspection | Follow the current manual | Perform during service and after any disturbance |
Include the ownership costs beyond cartridges
A useful budget includes the system, possible plumbing help, drilling, replacement filters, sanitation supplies, and water sent to the drain. Brondell's current specification material lists about 2.4 gallons of reject water per gallon of treated water under its conditions. Home pressure, temperature, chemistry, and use can change that result.
Check current replacement prices when you are ready to buy rather than relying on a fixed annual dollar estimate. Availability and promotions change, and the RF-20 and RF-40 expenses arrive on different schedules.
Who should choose the Circle layout
The RC100 is strongest for a household that wants certified tanked RO, has a suitable cabinet and faucet opening, does not want a powered pump, and prefers an enclosed system over exposed housings. The WQA certification trail and two-part maintenance plan make it easier to compare exact claims and ownership duties.
Choose an open-frame tank system when standard service access and broad replacement choices matter more than appearance. Choose tankless RO when a narrower cabinet footprint and higher on-demand flow justify electricity and proprietary quick-change cartridges.
Manufacturer and standards sources
Compatibility and instructions can change. Use these primary sources and your system manual for final confirmation.
Brondell Circle RC100 official product information ↗Brondell Circle RC100 specification sheet ↗Brondell RF-20 replacement set ↗Brondell RF-40 RO membrane ↗