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How Reverse Osmosis Systems Work
Water passes through pre-filters, then a semi-permeable membrane, then often a carbon post-filter, and is stored in a small tank. Rejected water goes to the drain. RO is excellent for drinking water, but it is a point-of-use system. It does not treat the whole house.
Under-Sink RO Installation and Faucet Connections
- Mount the filters and tankUnder the sink, with room for filter changes.
- Drill the faucet holeGranite, quartz and stainless need the right bit and care. Local homeowners call this the hardest part of a DIY install.
- Connect supply and drainA feed adapter on the cold line and a drain saddle or air gap on the drain.
- Start up and testWe flush the system, check for leaks and set the tank pressure.
Common RO System Leaks
- Push-fit tubing not fully seated
- Drain saddle not sealed
- Tank valve or housing O-ring
- Overtightened plastic fittings that crack
Filter and Membrane Replacement
Pre-filters are typically replaced more often, and the membrane lasts longer. Follow the manufacturer’s schedule and the condition of your water. Hard water shortens membrane life, which is why pairing with a softener helps.
What Affects RO Cost
| Factor | Effect |
|---|---|
| System quality | Cheap kits and premium systems differ in parts and certifications |
| Extra lines | Fridge or ice maker connections add parts |
| Countertop drilling | Stone needs special tools |
| Add-ons | Remineralization and alkaline stages cost more |
Local forum comments suggest basic RO units and professional installation can be inexpensive, while full packages with softeners cost much more. These are general ranges, not Stark quotes.
Seasonal RO Care
Spring
Sanitize the system once a year.
Summer
Check for leaks. Heat can affect tubing.
Fall
Replace filters before holidays.
Winter
Cold garage or exterior cabinets: protect lines from freezing.
Checklists
Before we arrive
· Tip: screenshot this list.
Questions to ask
· Tip: screenshot this list.
Myths vs. Facts
| Myth | Fact |
|---|---|
| RO replaces a softener. | It does not treat the whole house. It is a point-of-use system. |
| RO needs no maintenance. | Filters and membrane need scheduled replacement. |
| RO water is unsafe. | It is widely used. Some people add minerals back for taste. |
Our Estimate Process and What to Expect
- Call or text a photoTell us what you see. We tell you honestly whether it needs a visit and how urgent it is.
- Inspect and testA licensed plumber checks reverse osmosis installation and explains findings in plain language.
- Written estimateScope, materials, permits and exclusions in writing. No work starts without it.
- You approveYou choose. We never start before you say yes.
- Work, test, clean upWe finish, test, clean up and walk you through what changed.
Ask for our license number and verify it at tsbpe.texas.gov. Getting two or three written quotes is smart. Compare scope line by line, not just the total.
Reverse Osmosis Installation FAQs for San Antonio Homeowners
Can reverse osmosis connect to an existing sink?
Yes. We can drill for a dedicated faucet or use an existing hole if suitable.
What maintenance does an RO system require?
Replace pre-filters on schedule, replace the membrane as needed and sanitize periodically.
Does reverse osmosis replace the need for a softener?
No. RO is for drinking water at one tap. A softener treats hardness for the whole house.
How long does an RO install take?
A standard under-sink install usually takes a couple of hours.
Can RO feed my fridge?
Yes, with a dedicated line and the right tubing.
Why is my RO system leaking?
Usually a loose push-fit connection, a drain saddle or a cracked fitting.
About This Page and Our Sources
- San Antonio Water System — service, pressure, backflow program, 210-704-SAWS (7297)
- U.S. EPA: Drinking Water — general drinking water information
- Texas State Board of Plumbing Examiners — verify any plumber’s license
Check certifications for the contaminants you care about. Costs and requirements vary by property. Nothing here replaces an on-site inspection by a licensed plumber. Stark is not affiliated with SAWS, CPS Energy or any manufacturer named here.
