APEC Water Systems

Who are APEC Water Systems?

APEC stands for Advanced Purification Engineering Corp. The company was founded in 1997 and is based in City of Industry, California, where it designs, assembles and tests its reverse osmosis systems. It calls itself the leading US maker of home RO and whole house water purification, and its own site, apecwater.com, sells drinking water systems, countertop units, whole house filters and its sister range, Express Water.

Why buyers pick this brand:

• Certification. Systems carry the WQA Gold Seal, and the ROES-PH75 is listed to NSF/ANSI 58, the standard for reverse osmosis drinking water filter systems.
• Made in the USA. Each system is designed, assembled and tested in California; every RO-45 is lab tested for 8 hours before it ships.
• Ultra safe parts. The maker sells its range as "Certified Ultra Safe", with a lead-free faucet and food-grade tubing.
• Support. Lifetime technical support from WQA-certified water specialists, plus install videos.

In the UK you buy these systems through Amazon. Most listings are the US models, so the system is the same one American buyers get: US-made filters, a lead-free chrome tap, John Guest quick-connect fittings and food-grade tubing. That matters later when we talk about fittings and pressure.

How an APEC reverse osmosis system works

Every under sink water filtration system in the range follows the same layout. Tap water from your cold supply passes through:

1. Stage 1 - sediment filter. A 5 micron polypropylene cartridge traps sand, rust and grit, protecting everything after it.
2. Stages 2 and 3 - carbon blocks. Two extruded carbon block filters remove chlorine, tastes, odours and VOCs. Chlorine would otherwise damage the RO element.
3. Stage 4 - RO membrane. A high-rejection TFC membrane (Filmtec on the Ultimate range) removes up to 99% of total dissolved solids, plus arsenic, lead, fluoride, chromium and radium. The rejected water goes to the drain.
4. Stage 5 - post-carbon filter. A coconut shell carbon cartridge polishes the taste as water leaves the storage tank.
5. Extra stages. A calcium carbonate cartridge for remineralization on the alkaline models, and a UV lamp on the PHUV models to kill bacteria.

Filtered water is held in a pressurised 4 gallon (about 15 litre) tank and goes to its own tap, so your main mixer still runs unfiltered water for washing up. The system shuts off automatically when the tank is full, so it doesn't keep sending water to the drain overnight. Purified water from the tank is what you use for drinking, cooking and the kettle.

The APEC range compared

The brand splits its drinking water systems into the Essence series (compact, the most popular) and the Ultimate series (heavier duty, built to treat well water and awkward pressures too). Here is how the main models line up, using the maker's figures and the specs in our feed:

Model	Series	Stages	Output	Feed pressure	What's extra
ROES-50	Essence	5	50 GPD	40-85 psi	The standard model; about 3:1 drain to pure
ROES-PH75	Essence	6	75 GPD	40-85 psi	Calcium remineralization stage
ROES-PHUV75	Essence	7	75 GPD	-	UV lamp plus alkaline stage
ROES-100	Essence	5	100 GPD	-	1:1 pure to drain, 3/8" quick dispense line
RO-45	Ultimate	5	45 GPD at 60 psi	40-90 psi	Filmtec RO element, optional 14 gallon tank
RO-PUMP	Ultimate	5	-	0-30 psi	Built-in electric booster pump (120V US)
ROTL-600	Tankless	-	600 GPD	-	No storage tank
RO-CTOP-PHC	Countertop	4	-	Tap connection	No plumbing, alkaline stage

A gallon here is a US gallon (3.79 litres), so 50 GPD is about 189 litres a day and 75 GPD about 284 litres - far more than any household drinks. Output also drops with pressure: APEC rates the RO-45 at 45 gallons a day at 60 psi but 36 at 50 psi.

APEC Essence ROES-50 and ROES-100

The ROES-50 is the workhorse: five stages, WQA Gold Seal certified, built to remove up to 99% of over 1,000 impurities. It is the brand's best-known model and the one most reviewers start with. The ROES-100 doubles the output and cuts waste to a 1:1 pure-to-drain ratio, which the company says saves up to 300% of water, and its larger 3/8" outlet fills a jug faster. Neither is in our feed at the moment, so check them on Amazon if you want the plain five-stage reverse osmosis water filtration system without remineralization.

APEC ROES-PH75: the alkaline model

The ROES-PH75 adds a sixth stage of high-purity calcium carbonate that puts a little calcium back in and lifts the pH. Reverse osmosis water on its own can taste flat, because the membrane strips out minerals along with the contaminants; most people who choose it want great tasting water for drinking, tea and coffee.

In Water Filter Guru's lab test the ROES-PH75 cut TDS from 875 to 54 ppm (93%) and raised pH from 7.59 to 8.77. It removed all the fluoride and uranium in the sample of tap water, 98% of barium and 96% of strontium, but only 64% of nitrate and 49% of boron.

APEC Ultimate RO-45, RO-90 and RO-PUMP

The Ultimate series (RO-45 and the 90 GPD RO-90) uses 10 inch high-capacity filters that the maker says need changing once a year (about every 4,000 gallons). The RO-PUMP adds an electric booster for homes with 0-30 psi supply, but the model we list is the 120V US version, so it needs a step-down transformer in a UK kitchen. For a pumped system made for British sockets, look at our tankless reverse osmosis systems, which have a built-in pump.

Will APEC water systems work on UK water pressure?

This is the question most UK buyers miss. Every RO system pushes water through the membrane using mains pressure, and the Essence models need 40-85 psi of feed water, which is about 2.8 to 5.9 bar. Water companies only guarantee 0.7 bar at your boundary and aim for around 1 bar, according to WaterSafe. Many homes get much more than that, but some don't, so it is worth checking before you buy.

• Test first. A cheap pressure gauge on the kitchen cold tap tells you where you are.
• Over 4 bar (about 60 psi): any Essence or Ultimate system runs as designed.
• 2.8-4 bar: it works, but the tank fills more slowly and more water goes down the drain.
• Under 2.8 bar: that is below APEC's 40 psi minimum, so you need a booster pump or a tankless RO unit with its own pump.

Fitting an APEC RO system in a UK kitchen

The installation kit in the box contains almost everything you need:

• The filter housings and pre-fitted cartridges
• A 4 gallon pressurised storage tank and tank valve
• A lead-free chrome faucet for the sink
• A feed water valve and a drain saddle
• Food-grade tubing, Teflon tape and a housing wrench

An ice-maker kit is an optional extra if you want to feed a fridge.

Installation usually takes one to two hours if your sink already has a spare tap hole. Water Filter Guru took 90 minutes with an existing hole and drain. The usual order is:

1. Notify your water supplier (see below).
2. Turn off the cold supply and fit the feed tee.
3. Fit the faucet in a spare hole in the sink or worktop.
4. Clamp the drain saddle to the waste pipe above the trap.
5. Mount the unit and tank in the cupboard and push the tubing home.
6. Flush the system as the manual describes before you drink the water.

Fittings and adapters

The tubing is 1/4" (6.35mm), and the supplied feed adapters are US ½" to 3/8" threads. Most UK kitchens have a 15mm copper cold pipe, so buy a 15mm push-fit tee with a 1/4" outlet or a UK tap connector adapter before you start. Amazon reviewers report two common niggles: slow leaks at the threaded joints between the three pre-filter housings (fixed with PTFE tape) and filters that use a different tube size from the system, which needs a 3/8" to 1/4" reducer.

UK regulations

Fitting a reverse osmosis unit is one of the installations you must tell your water supplier about before you start, under the Water Supply (Water Fittings) Regulations 1999. The supplier can then check the drain and backflow arrangements. A WaterSafe-approved plumber can fit it and notify on your behalf.

APEC replacement filters: which set fits?

This is where the brand gets confusing, because each system has its own sets and some depend on the serial number. Use this table with the model name on your system's label:

Filter set	Fits	What's in it
FILTER-T2Y-ES50	Essence ROES series	Stages 1-3: sediment + 2 carbon blocks, high capacity
FILTER-T2Y-ESPH	ROES-PH75	Stages 1, 2, 3 and 6 (alkaline)
FILTER-MAX-ESPHUV-SS	ROES-PHUV75, serial AZ-PHUV-2999 and below	Complete 7-stage set incl. RO element and UV bulb
FILTER-MAX-ESPHUV-SSV2	ROES-PHUV75, serial AZ-PHUV-3000 and above	Complete 7-stage set
FILTER-MAX45-38	Ultimate RO-45 and RO-PUMP	5 stages incl. 45 GPD Filmtec membrane, 3/8" quick connect
FILTER-MAXCTOP-PH	RO-CTOP-PHC countertop	4 stages incl. RO element and alkaline cartridge
FILTER-SET-LITE	RO-LITE-180, 240 and 360	20 inch light commercial pre-filters
FILTER-MAX-TL600	ROTL-600 tankless only	Twist-and-pull replacement cartridges

How often to change APEC filters

The official maintenance schedule is 6-12 months for the sediment, carbon, inline and alkaline filters, and 2-3 years for the membrane (up to 4 years on some sets). Hard water and heavy use shorten that, and a cheap TDS meter tells you when the membrane is tiring: if the ppm reading from the RO tap creeps up, it's time. The "T2Y" sets are APEC's high-capacity versions for the Essence series, labelled "2 Year" for longer gaps between changes. Write the date on the housing when you fit them, and replace the UV bulb on PHUV models every 12 months.

Many APEC pre-filters are standard 10 inch cartridges, so they also fit most 5-stage reverse osmosis systems from other brands. That is handy if the official set is out of stock, though using genuine cartridges keeps the certified contaminant figures valid.

Does an APEC RO system remove fluoride?

Yes. The certified figures for the RO-45 show these reductions:

• Fluoride 97.7% and selenium 98.1%
• Arsenic 99.6% and hexavalent chromium 99.1%
• Heavy metals: lead 99.3%, cadmium 99.8%, copper 99.0%, barium 99.8%
• Radium 226/228 80.0%
• Chlorine, tastes and odours, through the carbon stages
• Bacteria and viruses, which the maker says the membrane also blocks; the UV models add a second barrier

The Water Filter Guru test removed all of it on the ROES-PH75 too. If your household relies on fluoridated water for dental health, the NHS advice on fluoride is worth reading, as fluoride toothpaste then does the work instead.

One caution: no filter catches everything. A Reddit user who tested their tap and filtered water through Tap Score found traces of antimony, arsenic and uranium after fitting a ROES-PH75. If you're treating a known contaminant, or a private or well water supply, test the water quality before and after. For private supplies the Drinking Water Inspectorate prefers whole-supply treatment to a single treated tap.

Waste water, taste and running costs

Every reverse osmosis system sends some water to the drain. The maker quotes about 3:1 for the Essence models (three gallons to drain for each one you drink) and 1:1 on the ROES-100. In testing the ROES-PH75 managed 1:5.1, and its real output was 42.74 GPD against the 75 claimed, at 48 psi. Higher pressure brings both figures closer to the box numbers.

The payoff is clean drinking water on tap for cooking, coffee, tea and ice, and no more buying bottled water or carrying plastic bottles home. The company backs its systems with a 30-day money back return, a 1 year warranty that extends to 2 years when you register, and lifetime phone and email support from WQA-certified staff, which reviewers on Amazon and Trustpilot regularly praise.

APEC RO systems: pros and cons

Pros

• WQA Gold Seal certified, with independent tests backing the 93-99% contaminant reductions
• No electricity needed on the tank models
• Standard 10 inch housings, so filters are easy to find and change
• Remineralization and UV options
• Lifetime support and a 2 year warranty when registered

Cons

• Needs 40 psi (2.8 bar) or more, which not every UK home has
• US fittings, so you need a 15mm adapter
• About 3:1 waste on most models
• Filter set names are confusing, and some depend on the serial number
• The pump model we list runs on 120V

APEC vs iSpring and Waterdrop

	APEC	iSpring	Waterdrop
Typical design	Tank, 5-7 stages	Tank, 5-7 stages	Mostly tankless
Best-known model	ROES-50 / ROES-PH75	RCC7AK	G3 / D6
Certification	WQA Gold Seal, NSF/ANSI 58 (PH75)	NSF on some models	NSF on some models
Needs power	No (except pump models)	No (except pump models)	Yes
Filter changes	Separate cartridges	Separate cartridges	Twist-off composite cartridges

APEC and iSpring are close rivals with very similar tank systems. Waterdrop and Frizzlife units are tankless and plug in, so they suit low UK pressure better and take up less room under the sink. If you'd rather not plumb anything in, a countertop RO system or an AquaTru countertop filter fills from a jug, and for more stages compare our 7-stage RO systems.

APEC Water Systems FAQs

Is APEC a good brand?

It is one of the most established RO makers in the US, founded in 1997, with WQA Gold Seal certified reverse osmosis drinking water systems and strong reviews for build quality and customer support. The common complaints are slow pre-filter thread leaks and confusing filter set names.

Where are APEC systems made?

They are designed, assembled and tested in City of Industry, California, and most filters are made in the USA too.

Do APEC systems need electricity?

No. The Essence and Ultimate tank systems run on mains water pressure alone. Only the pump models and some countertop units need power, and the RO-PUMP we list is a 120V US unit.

Will an APEC system fit UK plumbing?

Yes, with a 15mm to 1/4" adapter or tee for the cold supply. The drinking water tap needs its own hole in the sink or worktop, or you can reuse the hole of an existing filter tap.

Can I get APEC replacement filters in the UK?

Yes, through Amazon UK, as listed above. Stock on Amazon UK comes and goes, so it's worth buying a spare pre-filter set when one is available.

Does an RO system remove minerals?

Yes, it removes most of the calcium and magnesium along with the contaminants. The alkaline models add calcium back through their remineralization stage, and most people find that water tastes better.