Reverse Osmosis Systems Reference

Why this reference exists

Reverse osmosis (RO) is the most-installed water purification system in residential. Under-sink RO removes 95-99% of contaminants. Whole-house RO is premium. Service revenue: change visit, recurring every 6-12 months. This is the working framework for sale + install + service.

How RO works

Water passes through:

1. Sediment pre-filter (5-micron): catches dirt + rust
2. Carbon pre-filter: removes chlorine (would damage membrane)
3. RO membrane: semi-permeable membrane allows water but rejects dissolved solids
4. Carbon post-filter (polishing): final taste + odor
5. Optional remineralization: adds back beneficial minerals (some customers prefer mineral water taste)

Result: water with 95-99% of dissolved solids removed.

Waste stream: typically 3-5 gallons wasted per 1 gallon produced (newer systems 1:1 ratio).

RO product categories

Under-sink RO (most common):

• Standard 50-100 GPD (gallons per day)
• system + install
• Storage tank under sink (3-7 gallon)
• Dedicated faucet at sink
• Use for drinking + cooking only

Whole-house RO (premium):

• 500-1,500 GPD systems
• install
• Whole-house filtered
• Wastes more water
• Tankless models available

Tankless RO (newer):

• Direct-flow on demand
• No tank; smaller footprint
• 75-200 GPD continuous
• system + install
• Higher flow rate

Counter-top RO:

• Plug-and-play
• system
• No install required
• Counter footprint
• Limited capacity

For most: under-sink RO at kitchen sink. Whole-house if customer demands or significant water quality issues.

When to recommend RO

Strong fit:

• High TDS (total dissolved solids) > 500 ppm
• High dissolved hardness
• Specific contaminants (lead, nitrates, sodium, sulfate, fluoride concerns)
• Customer-driven (taste + safety + convenience)
• Pregnancy or infant in home
• High-end real estate market

Weak fit:

• Already-soft water with no contaminants
• Customer concerned only about taste (carbon filter cheaper alternative)
• Customer wants minerals (RO strips them; carbon doesn't)
• Customer can't accept waste water (RO wastes 3-5x produced volume)

Pre-install testing

Water test reveals what's actually in water:

• TDS: total dissolved solids in ppm
• Hardness: calcium + magnesium
• Iron + manganese: staining concerns
• Nitrates: well water concern
• Lead: pre-1986 plumbing concern
• Specific organics: chlorinated chemicals

Cost: (customer-paid pass-through).

For known good water + customer driven: RO at kitchen alone fine without full test.

For unknown water + significant decision: full test first.

Installation procedure

Under-sink RO standard install:

Step 1: Customer prep

1. Customer signs scope
2. Verify cold water supply line accessible
3. Drain access (typically under sink)
4. Sink hole for dedicated faucet (drill if needed)

Step 2: Mount system

1. Bracket on cabinet wall
2. Vertical orientation
3. 12-18" from supply tap

Step 3: Connect supply

1. Tap cold water supply line (saddle valve OR T-fitting)
2. Run flexible tubing to system inlet
3. Pressure-tight connection

Step 4: Tank install

1. Vertical orientation in cabinet
2. Connect to system output
3. Air bladder pressurization (typically 5-7 psi when empty; 35-40 psi when full)

Step 5: Drain connection

1. Drain saddle on sink drain pipe (above the trap)
2. Concentrate waste line from system to drain
3. Check valve to prevent backflow

Step 6: Dedicated faucet

1. Customer-chosen faucet (chrome, brushed nickel, etc.)
2. Drill hole in countertop if not pre-drilled
3. Faucet mounts on counter
4. Tubing from system to faucet underneath

Step 7: Initial fill + flush

1. Open supply valve
2. System fills tank (1-2 hours)
3. Flush first tank fully (discharge through faucet)
4. Refill + use

Step 8: Customer briefing

1. Filter change schedule
2. Dedicated faucet operation
3. Annual maintenance schedule
4. Warranty documentation

Service contract opportunity

RO customers benefit from regular service:

• Sediment pre-filter: every 6-12 months
• Carbon pre-filter: every 6-12 months
• RO membrane: every 2-5 years
• Post-filter: every 6-12 months
• Tank pressure check + recharge
• Annual visit:

At 100 customers the filter-change program becomes recurring revenue on the order of a service tech's annual billing.

Filter quality

Filter performance varies by brand:

Tier 1 (premium):

• iSpring, Aquasana, AO Smith
• 5-stage minimum
• Quality membranes (Filmtec, Dow)
• systems

Tier 2 (mid):

• Generic 5-stage systems
• Quality components
• systems

Tier 3 (budget):

• Off-brand
• Component quality variable
• systems

For pro install: tier 1 or 2. Budget systems fail or perform poorly.

Common pitfalls

• Wrong system size: too small for household consumption
• Bad water quality input: high sediment damages membrane fast
• No pre-filter: same as above
• Forgot drain saddle: drainage issue or leak
• Tank pressurization wrong: water flow restricted
• Membrane expired: customer didn't replace at 3-5 years
• No customer education: filters not changed; performance degrades
• Plumbing leak post-install: shutoff valve location matters

Customer questions + answers

"Will RO remove minerals?"

"Yes - 95-99% of dissolved solids including minerals. Calcium, magnesium, fluoride all removed. Some customers prefer remineralized RO (adds minerals back); others prefer mineral-free."

"How much water does it waste?"

"Traditional systems waste 3-5 gallons per gallon produced. Modern tankless systems: 1:1 or 2:1 ratio. Better for water conservation."

"How do I know when to change filters?"

"Sediment + carbon: every 6-12 months. Membrane: every 2-5 years based on water quality. We provide a maintenance schedule + reminder calls."

"What about waste water - can I redirect to irrigation?"

"Some systems allow redirection; check local code (some jurisdictions require RO waste to drain, not landscape due to high TDS in reject stream)."

"Does RO water taste different?"

"Yes - cleaner, less mineral taste. Some customers love it; others prefer mineralized water. Try before commit."

When NOT to install RO

Wrong fit: already-pure soft water (carbon sufficient), high water-waste intolerance, no drain access for whole-house, customer wanting mineral taste. Honest "not right for you" earns trust.

Service tips

Maintenance visits: customer consumption sized correctly, TDS in/out (membrane health), pre-filter inspection, membrane visual (slime/damage), tank pressure check, demonstrate clean water.

Customer talking points

For RO sale, lead with what it does and be equally direct about what it costs the customer in convenience. The RO sales that generate complaints are the ones oversold on day one.

• "This is the broadest treatment available at a tap." RO reduces dissolved contaminants that filters cannot touch, which is the honest reason it exists. Name the specific contaminant in their water report rather than listing everything RO can do.
• "It is for drinking and cooking, not the whole house." Set the boundary immediately. Whole-house RO is impractical for almost every residential customer, and a customer who expects treated shower water from an under-sink unit will be unhappy.
• "Your softener and your RO do different jobs." The softener protects the plumbing and appliances; the RO handles what you drink. Customers routinely believe one replaces the other.
• "It produces slowly and stores what it makes." Explain the tank. The unit does not deliver full flow on demand like a faucet filter; heavy back-to-back use can outrun the tank, and it refills over the following hours.
• "It sends water to the drain to make clean water." Say it before they read about it. Give the ratio for the specific unit you are quoting, and note that modern permeate-pump and high-efficiency units improve it considerably over older designs.
• "It has a maintenance schedule and it is not optional." Pre-filters on a regular interval, membrane on a much longer one. Put the schedule in writing and offer the reminder program at the point of sale, not later.
• "The taste will change." Cleaner and flatter, with less mineral character. Most customers prefer it; some do not. Offer a remineralization stage where the customer values mineral taste, and let them taste RO water before they commit.
• "Here is what it will not do." RO at the kitchen tap does not protect ice makers or other taps unless they are plumbed to it, does not disinfect on its own, and does not fix hardness anywhere else in the house.

Close on verification rather than on promises. Test their water, show the number, install, then test the treated water in front of them at the commissioning visit. A customer who has seen the before and after reading does not need to be convinced again at the first service call.

References

• NSF/ANSI Standard 58 (RO Drinking Water)
• EPA Safe Drinking Water Act
• WQA (Water Quality Association) certifications
• Manufacturer manuals (iSpring, Aquasana, AO Smith, Pelican)
• Manuall internal: Water Quality and Treatment Reference, Well Water Systems Reference