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💦 Elevate your hydration game with the ultimate under-sink alkaline RO system!
The ALK System by Express Water is a compact, NSF-certified 10-stage reverse osmosis and alkaline water filtration system that removes up to 99.99% of over 100 contaminants. It enriches water with essential minerals using Active Mineral Technology, delivers a fast 0.8 GPM flow rate, and installs easily under your sink without professional help. Designed for durability and convenience, it includes a 4-gallon storage tank and long-lasting filters, making it ideal for health-conscious professionals seeking premium, great-tasting water at home.









| ASIN | B00MU20LN2 |
| Best Sellers Rank | #17,178 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #32 in Under-Sink & Countertop Filtration |
| Brand Name | EXPRESS WATER |
| Capacity | 50 G/day |
| Container Type | Tank |
| Customer Reviews | 4.6 4.6 out of 5 stars (2,460) |
| Global Trade Identification Number | 00705332529525 |
| Included Components | Alkaline Reverse Osmosis System |
| Installation Type | Under Sink |
| Item Dimensions L x W x H | 15"L x 5"W x 17"H |
| Item Weight | 29.5 Pounds |
| Manufacturer | Express Water |
| Material Type | Alloy Steel, Brass, Plastic |
| Maximum Flow Rate | 0.8 Gallons Per Minute |
| Model Name | ROALK5D |
| Model Number | ROALK** |
| Other Special Features of the Product | NSF certified |
| Part Number | ROALK5D |
| Power Source | Water Pressure |
| Purification Method | Alkaline, Reverse Osmosis |
| Supported Water TDS Level Maximum (PPM) | 2000 |
| UPC | 705332529525 |
| Unit Count | 1 Count |
| Upper Temperature Rating | 100 Degrees Fahrenheit |
G**A
Great ro system
Water quality is great and taste great, smaller than other ro systems, super good for the price, easy to install, I had it for almost 2 years and haven’t had any issues, no noise and very duarable
S**F
Amazing and affordable
Simple and amazing! I live in a city with awful water; it’s terrible quality, full of forever chemicals, and tastes like dirt. We were slaves to one-use water bottles until this easy solution. Installation is simple enough and the customer service was excellent when I had questions. I’m an advanced-beginner home DIY-er and with the videos and written instructions, I installed this over a few days taking about 2 hours each day. I took my time double checking everything at each step. I experienced no problems or leaks. I’ve had it installed and running for about 3 weeks now. I did a lot of research for which filter to use, both brand and type. RO with remineralization is the best way to go. This brand does it all and at a great price with easy self installation. I would recommend this to everyone, seriously. It does require a separate beverage faucet, which I thought I didn’t want at first. I thought wanted every drop of water in my kitchen sink fully filtered. But without pricey full-house filters, that can’t be achieved. This is a nice alternative that lets you keep water pressure for washing dishes. The beverage faucet itself has great flow rate. Size: I have a small amount of space under my cabinet because I have a large disposal underneath. It still fits beautifully and I even have space for a little bit of storage under the sink. I have a one drain sink with a disposal, and I had to buy a separate attachment to make sure the filter drains properly. A plumber gave me the attachment tip. We’ve been making ice and drinking clean, great tasting water and we’re so thankful for this affordable and amazing product. Get it.
R**.
Excellent Product, Would definitely recommend!
Very Pleased with this product so far! Got it in a Double box that included everything organized by box and extremely well packaged. Faucet is very sturdy and clean looking, all stainless and feels heavy duty. Components are very well made. Price point is just great! Installation took about 1 hour following video instructions (available on Youtube). Everything fit just right without leaks on the first try. (Be Careful when installing plastic threading on metal components. Make sure that the threads are straight and you'll have no problems) Follow the manufacturers recommendation for system flushing and youre all set. Installation requires drilling to tap the drain before the P trap and if you have to drill a hole for the faucet. Other than that, the rest is just Screws and Pressure Fittings. Water Quality is the best! Re mineralization adds those minerals that help with hydration, alkalinization and de ionization takes that water to heavenly status! Would recommend any day!
F**R
Love this filter kit.
Love this filter. Install was easy with the provided instructions. I have it hooked up to my ice maker as well. Water never looked so clean and tastes great!
A**E
Great value
I bought this system about midway through 2025 and have had zero issues with it. This does an excellent job of filtering out all the nasty particles and tastes from our city water. Hook up was very easy to install. Love this filtration system and it is very affordable.
I**D
Fully As Described. Works Great
As some others have noted, installation is straight forward and a bit of a challenge for the plumbing novices out there. It can be done without getting too upset, I assure you :) The directions are easy to understand. The color connections and water hoses make connecting the correct line to the correct filter simple. Mounting the unit in the cabinet under the sink can have its challenges, especially if the space is unusual in some way. I only had one place to mount the filter holding unit, and it was not in a convenient location to get to; behind and within inches of the sink drain pipes. Maybe asking a friend with an easy going attitude to help could make the process more enjoyable? lol And let's face it folks, you are going to ENJOY this product. Are you over fifty and wanting to remember what it was like visiting a family member's farm for a totally refreshing glass of cool, satisfying water? (probably from a well system) Are you under fifty and wishing family farms were still around for you to get a body nourishing glass of water from? Then you have chosen correctly. This filtration system brings to mind what water used to be like for me as a child. This product is designed and constructed with integrity. That's a fancy way of saying you won't feel like you over paid for a water filtration system. The packaging was clearly marked, and contained all listed items required for a successful installation. (minus the attitude adjustment - lol) I personally have paid for water delivery for over 8 years now and am looking forward to lowering the cost. I would recommend this product. One last piece of advice: Make sure to give yourself enough time on installation day. The filters need to be primed, as well as the holding tank filled and drained several times to ensure a quality product is delivered to your new faucet. And in my case I needed some extra time for color coded lines and fittings, and colorful language too :)
R**5
Easy instructions with pictures!
We love this system! Complete setup easily explained in book of instructions! Awesome price n water tastes so good we use it for cooking n icecubes! Price was fantastic n so far very pleased w the quality!
G**.
Muy muy bien, no tuve que llamar a algún técnico, te dice todo de como instalarlo, el agua sabe muy bien, también lo conecte a mi refrigerador y listo agua y hielos, estoy muy satisfecho por el sistema espero vendan los empaques o refacciones por si se necesitan
J**O
For the money this is hands down one of the best systems. It was easy to install. The flavour of the alkaline water is great. We hooked it up to the fridge so it took a bit more to install it because of all the filling and emptying you need to do to get it set up. Before connecting it, I hooked up the faucet temporarily and drained it into the sink. The first day or two, there was a strange rubber-like flavour in the water. This is normal. The rubber bladder inside the tank needs a few cycles of expansion and contraction to loosen up. If you get that flavour or rubber, all you need to do is to completely drain the tank 2 times and then it’s gone. But make sure you drain it to the point where the water comes out as a trickle and you’ll know it’s completely empty. I have had it for 5 months and I think it’s ready for the first filter change. We have not had a single problem with the system. It does make a funny sound every once in a while but that’s just the bladder making noise. It’s a great product at a great price. Very well packaged and easy to understand instructions. It took me only 45 minutes to set it up.
L**S
El producto llego a tiempo y es de muy buena calidad. No fue fàcil de istalar pues hubo que pasar una manguera hacia el refrigerador y fue un poco complicao pero por el sabor del agua, valiò la pena
T**C
The small town I live in is terrible with their water system. If it doesn't smell like chemicals and yellow looking. It smells like frog water and is more brown than yellow in color. I installed this unit and now my water is great. No nasty smell. No nasty tasting water. No nasty film on dishes or in the pet's water dishes. The water comes out clear with no smell other than clean drinkable water. I only wish our town water treatment plant used this kind of system. I bought this for my brother's house warming gift and they love it as well. It was easy to install and the color coded tubes make for a snap as to what goes where. I looked around for water systems in my area and this was by far the better price than what was locally available. Had some issues with getting a refill set to come to my area off Amazon, but the company handled that fast and easily when I contacted them to notify them of the issue.
J**.
Where do I start? Firstly I was originally going to get the Big Berkey. But the more I thought about it the more I realised that this was far better value for money. The product came very well packaged. And it was very easy to figure out how to install the unit. One thing that should be noted though is that you need to take your time. Check and recheck before you do anything. And don't skip any steps. Treat the unit and the filters with allot of care. It just takes one good bump to crack something and then your done. Once installed follow the start up process. Flushing the system 4 or 5 times fully. I did 8. By the end of the flushing the water will be so pure it has virtually no taste. It's like drinking silk. It's delicious and so refreshing.
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