RO Membrane Replacement Cost: $62.99 a Year, Carbon Stages $183.98

A replacement RO membrane for Aquasana’s SmartFlow costs $62.99 and lasts 12 months, per Aquasana’s membrane replacement page (read 2026-10-23). That is $62.99 a year.

The carbon stages cost more. Aquasana’s carbon block replacement pair is $91.99 and lasts 6 months, so a year of carbon is 2 × $91.99 = $183.98. The membrane is about a quarter of the yearly bill: $62.99 ÷ ($62.99 + $183.98) = 25.5%. Before you order a membrane, check the prefilters and a TDS reading (total dissolved solids) to make sure the membrane is the part that failed.

Every price here comes from the maker’s own store, with the date it was read. The same rows sit in our water filter cost table, which re-reads each maker’s page every day.

Membrane or prefilters? Fresh prefilters and a TDS reading settle it

Weak flow at the RO faucet does not prove on its own that the membrane is worn out. The Water Hub’s membrane replacement guide says what to do first: “Change overdue prefilters first and retest.”

To retest you need a TDS meter, which reads the dissolved minerals and salts in the water. Take one reading at the kitchen tap and one at the RO faucet. The Water Hub’s rule is this: if flow stays weak with fresh prefilters, or the RO reading keeps climbing toward the tap’s reading, “the membrane itself is exhausted.”

That order also matches the money. On the SmartFlow, a carbon pair is $91.99 and a membrane is $62.99, and the carbon is due twice as often. A fresh prefilter will not bring down an RO reading that keeps rising, though, and that is the sign the membrane is done.

One RO system’s carbon costs 2.9 times its membrane each year

Prices below are each maker’s list price on its own store, read on the date shown. The Aquasana rows were read 2026-10-23; the APEC and iSpring rows come from each brand’s catalog feed as logged in the filter cost table (APEC 2026-10-23, iSpring 2026-10-22).

Part (maker)	Price	Rated life	Cost per year
SmartFlow RO membrane (Aquasana)	$62.99	12 months	$62.99
SmartFlow carbon pair, stages 1 and 3 (Aquasana)	$91.99	6 months	2 × $91.99 = $183.98
SmartFlow membrane + carbon, one year	$62.99 + $183.98	12 months	$246.97
ROES-PH75 1-year filter set (APEC)	$89.99	1 year	$89.99
ROES-PH75 2-year filter set (APEC)	$179.99	2 years	$179.99 ÷ 2 = $90.00
RO10001F all-in-one cartridge FPCM1000 (iSpring)	$159.99	up to 24 months	$159.99 ÷ 2 = $80.00

Three things stand out:

1. On the SmartFlow, carbon costs $183.98 ÷ $62.99 = 2.9 times the membrane each year.
2. APEC’s 2-year set saves nothing: $179.99 against 2 × $89.99 = $179.98. Buy the 1-year set and keep the cash.
3. iSpring’s RO10001F puts the membrane inside one cartridge with the sediment and carbon stages. Its catalog text says the cartridge “combines PP sediment, activated carbon, 0.0001 μm RO membrane, and taste-polishing carbon into one compact cartridge.” So every membrane change there is a $159.99 change.

The SmartFlow system itself was $224.99 on 2026-10-23, marked down from a $449.99 MSRP on Aquasana’s product page. At that sale price, one year of membrane and carbon ($246.97) costs more than the system.

Standard membranes can be shopped around; single-cartridge designs cannot

The Water Hub sums up what drives the price: “Standard elements are commodity items and proprietary ones cost more.” A standard element is interchangeable, so you can price it at more than one seller. A proprietary element fits one brand.

The makers here sit at both ends. APEC’s ROES-PH75 page lists stage 4 as a “FILMTEC Reverse Osmosis Membrane”, a named membrane brand. The SmartFlow membrane is Aquasana’s own part: its page says it replaces the membrane of the SmartFlow (AQ-SFRO and AQ-SFRO2). The iSpring RO10001F goes further and folds the membrane into one composite cartridge.

The weak spot of a proprietary design is that you cannot shop it. The upside is fewer parts to track: iSpring rates its one cartridge for up to 24 months, the longest life in the table. Who should skip a single-cartridge system: if you want to replace only the membrane when a TDS check says it is worn, buy a system with a separate standard-size membrane. If you already own one, price its next cartridge now, before the old one fails.

Match the old part exactly. The Water Hub says membranes are sized by production rating, and a higher-rated one only helps if your flow restrictor matches it.

Aquasana’s auto-ship takes the SmartFlow year from $246.97 to $209.92

Aquasana lists a second price on both replacement pages: $53.54 for the membrane and $78.19 for the carbon pair, “15% OFF + Free Shipping” through its auto-ship plan. A year on that plan costs $53.54 + 2 × $78.19 = $209.92, which is $37.05 less than buying each part at list.

The catch is the schedule. Auto-ship sends parts on Aquasana’s calendar, while The Water Hub’s advice is to let the TDS reading decide when the membrane goes. If your readings say the membrane still has life, a membrane shipped at month 12 sits on a shelf.

The carbon matters more than its price. The Water Hub says chlorine destroys thin-film membranes, and the carbon stage keeps chlorine away from the membrane. It also says hard water scales membranes, so with hard water, budget from the short end of any rated life.

You can swap the membrane yourself

The Water Hub’s answer to “Can I replace an RO membrane myself?” is “Yes”. Aquasana says its SmartFlow parts are made for easy replacement: “Simply pop out and replace.” If you do it yourself, The Water Hub says to flush the preservative out of the new membrane before you use the water.

Checklist before you order a replacement membrane

1. Replace overdue prefilters and retest. The Water Hub puts this first. On the SmartFlow, the carbon pair is the part due every 6 months ($91.99).
2. Compare TDS at the RO faucet with TDS at the tap. If the RO reading keeps climbing toward the tap’s, The Water Hub says the membrane is worn out.
3. Check flow with the fresh prefilters in. If it is still weak, the membrane is worn out (The Water Hub). If flow and TDS both came back, stop: the prefilters were the fix.
4. Find out whether your system takes a standard or proprietary membrane. A standard one (APEC names FILMTEC) can be priced at several sellers; a single-cartridge design like the RO10001F cannot.
5. Price the part on the maker’s store and in the filter cost table. The table shows the date each price was read and logs every change.
6. Count the whole year, not just the membrane. On the SmartFlow that is $246.97 at list or $209.92 on auto-ship; on APEC’s ROES-PH75 it is $89.99.

FAQ

How often does an RO membrane need replacing? Aquasana rates the SmartFlow membrane for 12 months, and iSpring rates its all-in-one RO10001F cartridge for up to 24 months. Use the rating as a reminder to run the TDS check, and let the reading decide.

Why does one membrane cost more than another? Standard elements are commodity parts and proprietary ones cost more, per The Water Hub. A single-cartridge design also bundles the other stages into the price.

Can I use a new membrane straight away? Not until you have flushed out its preservative, per The Water Hub.

Run the TDS check, count the full year of parts, then order. More yearly cost breakdowns are in CentsPerGallon’s filter cost guides.