Not sure if you need the 4-stage, the 5-stage, or a different RO entirely?The right pick depends on your chlorine level, feed pressure, and what you want the water to do. Call or text Aidan with your water details (or send your test results) and he will tell you in a couple of minutes whether the $275 4-stage covers you, the 5-stage is worth the extra $50, or your situation actually calls for a certified system. Honest answers before you spend anything.
Complete MAW-50 Under-Sink RO System (Both Configurations)
✓50 GPD Toray thin-film composite RO membrane (TFC-50) - the stage that does the dissolved-solids removal work
✓Clear sediment pre-filter housing - see the sediment cartridge load at a glance, no guessing when it is time to change
✓Double o-ring filter housings - a second seal on every housing for leak protection under your sink
✓3.2 gallon NSF-approved storage tank - filtered water is made ahead and waiting at the faucet
✓Chrome long-reach lead-free faucet - the dedicated drinking water tap for your sink
✓Push-connect fittings with 3/8" faucet tubing - no soldering, no special tools
✓Angle stop adapter valve - taps the cold line cleanly during install
✓Filter wrench - included for housing changes
✓ Free shipping to all lower 48 states
4-stage vs 5-stage: the 4-stage runs sediment, carbon block, RO membrane, and inline carbon post-filter. The 5-stage adds a second carbon block pre-filter ahead of the membrane, which is the right pick on heavily chlorinated city water because chlorine is what wears out RO membranes.
System Overview
System Type
Under-sink reverse osmosis, tank-based (point of use)
40 psi or higher recommended (no booster pump needed above 40 psi)
Electricity
None required - runs entirely on line pressure
Tools Included
Filter wrench
Filtration Train by Configuration
4-Stage (NRO4-50) - $275
Sediment pre-filter (clear housing)
Carbon block pre-filter
50 GPD RO membrane
Inline carbon post-filter
5-Stage (NRO5-50) - $325
Sediment pre-filter (clear housing)
Carbon block pre-filter
Second carbon block pre-filter
50 GPD RO membrane
Inline carbon post-filter
The 5-stage's second carbon block doubles the chlorine contact ahead of the membrane. Chlorine is the main thing that degrades TFC membranes, so on heavily chlorinated city water the extra $50 buys longer membrane life and better taste protection.
Certifications, Stated Honestly
Storage Tank
NSF-approved
System Certification
This system is not NSF/ANSI system-certified. If you want full NSF/ANSI 42 + 53 + 58 system certification, see our FreshPoint 4-stage RO ($795). For certified PFAS reduction, see the PFAS RO system ($895).
Standard under-sink install with push-connect fittings, no electricity needed. The angle stop adapter valve taps the cold line, the 3/8" tubing feeds the included faucet, and the 3.2 gallon tank sits in the cabinet corner. Most homeowners finish in 1-2 hours.
Check feed pressure and well water pre-treatment first. The system needs 40 psi or more at the cold line; below that, RO production slows and a booster pump is worth discussing. On well water, iron, hardness, and heavy sediment must be treated upstream or they will foul the membrane in months instead of years. Send us your water test and we will confirm the setup before you buy.
Installation Steps
Shut off the cold water supply under the sink and relieve pressure at the faucet
Install the angle stop adapter valve on the cold line
Drill the faucet hole (or use an existing sprayer hole) and mount the chrome long-reach faucet
Mount the filter manifold in the cabinet and position the 3.2 gallon storage tank
Connect feed, tank, faucet, and drain lines with the push-connect fittings
Turn the water on, check every connection, and let the tank fill (first fill takes a few hours)
Drain and discard the first 1-2 tanks of water to flush the new cartridges and membrane
Need help? Call or text Aidan at 800-460-5810, 7 days a week. Send your water test results and we will confirm whether the 4-stage or 5-stage fits your water and walk you through the install.
✨
Two consumables, predictable costs. A $49-$59 filter pack every 6-12 months and a $135 membrane every 2-3 years. The clear sediment housing lets you see the pre-filter loading up, so you change filters when your water says so, not on a guess.
Maintenance Schedule
Every 6-12 MonthsReplace the filter pack. The MAW-50 replacement filter pack covers the sediment, carbon block(s), and inline carbon post-filter: $49 for the 4-stage pack, $59 for the 5-stage pack. Change at 6 months on chlorinated city water or sediment-heavy wells, 12 months on cleaner feeds.
Every 2-3 YearsReplace the RO membrane. The TFC-50 replacement membrane ($135) is the same Toray thin-film composite element the system ships with. Replace sooner on hard or high-TDS water; a cheap TDS meter on the RO faucet tells you when rejection is slipping.
How to Change Filters
Close the feed valve and the tank valve, then open the RO faucet to relieve pressure
Spin the housings off with the included filter wrench - the double o-rings reseal cleanly
Swap cartridges, hand-tighten the housings, reopen the valves, and flush the first tank
Tip: staying on the filter schedule is what protects the membrane. Pre-filters cost $49-$59 a year; a chlorine-damaged membrane costs $135 plus weeks of flat-tasting water. Questions? Call or text 800-460-5810.
A 50 GPD Toray membrane, standard low-cost replacements, and honest answers about what the price does and does not buy
The MAW-50 is our value-tier under-sink reverse osmosis system: real RO technology at $275 for the 4-stage or $325 for the 5-stage. The heart of the system is a 50 GPD Toray thin-film composite membrane, the same membrane technology used in systems costing three times as much, which rejects dissolved solids that no carbon pitcher or fridge filter can touch: TDS, lead, fluoride, nitrates, and sodium among them.
The build is practical where it counts. Double o-ring housings seal every filter stage twice. The sediment pre-filter housing is clear, so you can see the cartridge loading up and change filters when your water says so. The 3.2 gallon NSF-approved storage tank keeps finished water pressurized and ready at the included chrome long-reach lead-free faucet. Push-connect fittings, 3/8 inch faucet tubing, an angle stop adapter valve, and a filter wrench round out the box. No electricity needed: the system runs entirely on line pressure (40 psi or more recommended).
Ownership costs stay low because the housings take standard-format cartridges: a $49-$59 filter pack every 6-12 months and a $135 TFC-50 membrane every 2-3 years. We are honest about what the price leaves out: this system is not NSF/ANSI system-certified (the tank is NSF-approved). If certified performance numbers matter to you, step up to our NSF-certified FreshPoint RO at $795 or the certified PFAS RO at $895. If you want the most water for the least money, this is the one.
✅ Us3.2 Gallon Pressurized Tank at a Dedicated Faucet
❌ ThemSlow Pitcher Refills, Constant Waiting
Daily Capacity
✅ Us50 GPD Membrane (a Family Drinks 2-4 Gal/Day)
❌ ThemA Few Gallons a Day, Refilled by Hand
Filter Schedule
✅ UsFilter Pack Every 6-12 Months
❌ ThemNew Cartridge Every 1-2 Months
Annual Filter Cost
✅ Us$49-$59 Filter Pack Per Year
❌ Them$60-$120+ in Pitcher/Fridge Cartridges
Cooking Water
✅ UsFill Pots Straight From the RO Faucet
❌ ThemImpractical Beyond Drinking Glasses
Expert Support
✅ Us7-Day Phone, Text & Email
❌ ThemLimited or None
✔ Expert Drinking Water Support
From sizing the right configuration to install guidance to filter change reminders, Aidan provides hands-on support at every step. Real person, real expertise, 30+ years of water treatment experience. No bots, no scripts.
📞 Call Us800-460-5810
✉️ Email Supportsupport@midatlanticwater.net
🕒 Live Hours7 days a week
Frequently Asked Questions
Yes, comfortably. A family uses roughly 2 to 4 gallons a day for drinking and cooking, and the 50 GPD membrane produces far more than that over a day. The 3.2 gallon NSF-approved storage tank means the water is already made and pressurized when you open the faucet, so you are never waiting on the membrane in real time. Where 50 GPD gets tight is unusual cases: very large households, feeding an ice maker and a coffee station and an aquarium off one system, or cold feed water (membrane output drops as water gets colder). If that sounds like you, the 75 GPD Pure-75 is the step up. For a typical family kitchen, 50 GPD is plenty.
The difference is one extra carbon block pre-filter ahead of the membrane. Chlorine is the main thing that degrades thin-film composite RO membranes, so the second carbon block on the 5-stage ($325) buys extra chlorine protection and longer membrane life. Our honest rule: heavily chlorinated city water, pick the 5-stage. Well water (no chlorine) or lightly treated municipal water, the 4-stage ($275) does the same job and the extra stage would mostly sit idle. Not sure how chlorinated your water is? Call or text us at 800-460-5810 and we will tell you in two minutes.
Not if your home has 40 psi or more at the cold line, which covers the large majority of homes on city water and pressure-tank wells. RO membranes are driven by feed pressure: above 40 psi the system produces at its rated speed, and no electricity is needed at all. If your home runs below 40 psi (some wells with low pressure switch settings, some rural systems), production slows and the tank fills sluggishly; a booster pump fixes it, and we can talk you through whether you actually need one before you spend the money.
Two consumables. The filter pack (sediment, carbon block or blocks, and inline carbon post-filter) changes every 6 to 12 months: $49 for the 4-stage pack, $59 for the 5-stage pack. The TFC-50 membrane changes every 2 to 3 years at $135, sooner if your water is hard or high-TDS. So a typical year of ownership costs $49-$59, with the membrane adding about $45-$65 per year averaged over its life. The clear sediment housing helps you time it: when the cartridge looks loaded, change the pack.
Yes. The RO membrane physically rejects dissolved solids, which is what carbon-only pitchers and fridge filters cannot do. That covers TDS, lead, fluoride, nitrates, sodium, arsenic, and most other dissolved contaminants at high percentages. One honest caveat: this system's performance is not NSF/ANSI system-certified (the storage tank is NSF-approved; the system as a whole has not been through certification testing). RO as a technology is proven for these contaminants, but if you want third-party certified numbers on paper, our FreshPoint RO ($795) carries NSF/ANSI 42, 53, and 58 system certification, and the PFAS RO ($895) adds certified PFAS reduction.
Yes. RO water is safe and removes the contaminants people actually worry about: lead, arsenic, nitrates, and dissolved solids. It also removes minerals like calcium and magnesium, which is the concern you may have read about, but in a normal diet those come overwhelmingly from food, not water. Some people notice RO water tastes flat at first because the minerals are gone; most come to prefer it within a week. If remineralization matters to you, ask us about adding an alkaline post-filter inline.
Most homeowners with basic DIY comfort can, in 1 to 2 hours. Everything connects with push-connect fittings, the angle stop adapter valve taps the cold line without soldering, the chrome long-reach faucet is in the box, and the filter wrench is included. The most involved step is drilling the faucet hole if your sink has no spare sprayer hole. No electricity is required. If you would rather not, any local plumber can do it in about an hour, and you can call or text Aidan at 800-460-5810 with questions either way.
Yes, with one condition: the membrane needs protection from whatever else is in the well. RO handles dissolved contaminants beautifully, but iron, hardness, and heavy sediment will foul a membrane in months if they reach it untreated. If your well has iron staining, hardness, or sulfur smell, those need dedicated treatment upstream of the RO. Start with a water test, send us the results, and we will tell you honestly whether your well needs pre-treatment first or whether the MAW-50 can go straight in.
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MAW-50 Reverse Osmosis...$275.00
The Value Tier, Explained Honestly
Real RO Technology at $275, and What the Extra Money Buys Elsewhere
What You Get With Pitchers, Fridge Filters, and Premium RO
Pitcher and fridge filters look cheap until you do the math. They rely on carbon alone, which handles chlorine taste but cannot reduce dissolved solids at all: no TDS, no lead certification on most models, no fluoride, no nitrates. The cartridges change every 1 to 2 months at $60-$120+ per year, the pitcher holds half a gallon, and filling a pasta pot from one is a joke.
At the other end, big-brand under-sink RO systems run $450-$850 and are excellent, but a lot of that price buys conveniences (tankless form factors, app connectivity, proprietary cartridges) rather than better water.
The Real Cost Comparison
Pitcher / Fridge Filter
$30-$60 + cartridges
❌Lifespan: Fails in 3-4 years
❌Result: Frequent repairs, poor water quality, leaks
❌Support: None
$60-$120+/yr in cartridges, no TDS or lead reduction, hand-filled
Ten-year math: the MAW-50 costs $275-$325 up front, then $49-$59 a year in filter packs and a $135 membrane every 2-3 years, roughly $1,300-$1,500 total over a decade of unlimited RO water for drinking and cooking. A pitcher habit costs $60-$120 a year in cartridges, never touches your dissolved solids, and you fill it by hand the whole time. The MAW-50 pays for itself against bottled water in the first few months.
What You Get With the MAW-50
The MAW-50 is the affordable workhorse of under-sink RO: a 50 GPD Toray thin-film composite membrane, the same core technology as systems costing three times as much, in a standard-format housing design that takes inexpensive industry-standard replacements. Double o-ring housings for leak protection, a clear sediment housing so you can see filter loading, a 3.2 gallon NSF-approved tank, a lead-free chrome faucet, and push-connect fittings, all in the box at $275 for the 4-stage or $325 for the 5-stage.
We are honest about the trade-off: this system is not NSF/ANSI system-certified (the tank is NSF-approved; the system has not been through certification testing). If certified numbers matter to you, our FreshPoint RO ($795) and PFAS RO ($895) carry them. If you want proven RO technology at the lowest cost of ownership, this is the one we recommend.
Contact Us
800-460-5810
We're here to help.
30-Day Risk-Free Guarantee
30 days from installation to verify the water with your own TDS meter
If this system does not deliver the low-TDS drinking water you bought it for within 30 days of installation, contact us and we will make it right: troubleshooting your feed water and install, replacing a component, or issuing a full refund. No restocking fees. No shipping a system back at your expense before we have even tried to fix it. No runaround.
10,000+Systems Installed
455+Verified Reviews
30+Success Rate
Reverse osmosis results are measurable: put a $10 TDS meter on the RO faucet and the number tells you whether the membrane is doing its job. You should have time to install the system, measure the water, and confirm the fix before you are locked in. We have spent 30+ years helping homeowners solve water problems, and we back the MAW-50 the same way we back our $3,000 systems.
The Industry "Return Policy" Trap
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Most online water treatment retailers offer a return policy that requires you to ship the system back at your expense and then deducts a 15-25% restocking fee. It is designed to make returns impractical. We do not operate that way at any price point, including our value tier.
How Our Real Guarantee Works
1
The Water Isn't Right
If the TDS reading at the RO faucet isn't dropping the way it should, or the system isn't producing, that's on us to figure out with you.
2
You Call Us, We Fix It
We troubleshoot together: feed pressure, tank pre-charge, membrane seating, flush cycles. Most issues are a low-pressure feed or a skipped first-tank flush and are resolved in one call.
Full Refund, No Hassle
If we cannot resolve the issue, you get a full refund. We handle the logistics. That is the difference between a real guarantee and a return policy.
The MAW-50 is the system I recommend when someone calls and says they just want clean-tasting, low-TDS water for drinking and cooking without spending $800. It uses the same Toray membrane technology as the premium systems, and the standard housings mean replacement filters cost $49-$59 a year instead of $150+. I will tell you straight on the phone whether the 4-stage or 5-stage fits your water, or whether your situation actually calls for a certified system instead.
