Stokk Tankless Reverse Osmosis System: Fast, Smart 8-Stage Water Filter Review

As a seasoned reviewer with many years of experience testing under-sink and countertop water filtration systems, I understand how important clean and safe drinking water is for every home. I have carefully researched and personally tested the Stokk Tankless Reverse Osmosis System, 800 GPD Fast Flow Water Filter, to provide you with honest and detailed insights. This review is based on thorough evaluation of its features, performance, and certifications such as NSF/ANSI 58 & 42, ensuring you get reliable information. My goal is to help you make a smart and confident choice when selecting a water filter that fits your needs and keeps your family healthy.

Pros & Cons

What We Loved

• ✅ Fast 800 GPD water flow
• ✅ 8-stage filtration removes 1000+ contaminants
• ✅ Certified NSF/ANSI 58 & 42 and FCC
• ✅ Efficient 3:1 pure to drain ratio
• ✅ Smart faucet with instant fresh water

What Could Be Better

• ❌ Installation may require plumbing skills
• ❌ Initial cost higher than basic filters
• ❌ Replacement filters add to maintenance cost

Who Should Buy This

This Stokk Tankless Reverse Osmosis System is perfect for anyone who wants clean and safe drinking water right from their sink. It is great for families who worry about harmful chemicals like PFAS in their water. If you want a fast flow water filter with 800 gallons per day capacity, this system works well. It fits under the sink and saves space because it has no tank. The smart faucet makes it easy to use every day. Plus, it is certified to high standards, so you can trust the water quality.

If you have very low water pressure or a very small household, this system might be more than you need. Also, if you prefer a filter that is simple with fewer stages or want a cheaper option, this might not be the best choice. People who do not want to install anything under their sink or have limited space there may want to consider other options. This system needs a bit of setup and maintenance to keep working well.

Technical Specifications

Key Details

• Brand: Stokk
• Model: S2
• Size: 14.92″ x 5.91″ x 18.11″
• Weight: 34.85 lbs
• Material: High-grade durable plastic and stainless steel components
• Color Options: White
• Special Features: 8 Stage Reverse Osmosis Filtration, Tankless Design, 800 GPD Fast Flow, 3:1 Pure to Drain Ratio, Smart Faucet, PFAS Reduction, NSF/ANSI 58 & 42 Certified
• Warranty: Manufacturer’s standard warranty (refer to product manual)

Our Testing Experience

First Impressions

When I first unpacked the Stokk Tankless Reverse Osmosis System, I was impressed by its compact size and sleek design. Setting it up under my kitchen sink was straightforward thanks to the clear instructions. I scanned the QR code to check the SGS test report, which gave me confidence right away. The smart faucet looked modern and felt sturdy, which made me curious to see how fast and clean the water would be.

Daily Use

Using the Stokk system every day quickly became a part of my routine. I loved how fast it delivered water — just a few seconds to fill my glass, which is great when I’m in a hurry. The water tasted noticeably fresher and cleaner compared to my old filter. I also appreciated that it didn’t take up much space under the sink, leaving room for other essentials. The smart faucet was easy to operate, and I liked the peace of mind knowing it was reducing harmful substances like PFAS and chlorine.

Key Features in Action

The 8-stage filtration really stood out during testing. It removed so many contaminants, including those I didn’t even know were in tap water. The NSF/ANSI 58 & 42 certification was reassuring, and I could tell the water was pure by the taste and clarity. The 800 GPD fast flow meant no waiting around for water to filter, and the 3:1 pure to drain ratio saved a lot of water compared to my previous system. These features combined made the system both efficient and eco-friendly.

Long-Term Performance

After using the Stokk system for several weeks, it continued to perform reliably without any drop in water quality or flow speed. The filters seemed durable, and maintenance was simple. I felt confident drinking the water daily, knowing it was consistently clean and safe. Overall, the system proved to be a solid investment for anyone wanting fast, pure water without wasting much water.

How It Compares

Side-by-Side Comparison

Feature	Stokk Tankless RO System S2	Waterdrop G3P600 RO System	Stokk RO System S1
Price	See Price	See Price	See Price
Quality	Certified by SGS against NSF/ANSI 58 & 42 and FCC listed. High filtration quality removing 1000+ contaminants by 99.99%, including PFAS, fluorides, chlorides, and more.	NSF/ANSI 42, 58 & 372 certified, plus FCC, EU, and UKCA safety standards. Officially lab tested to reduce TDS, PFAS, heavy metals, radioactive substances, and chemical contaminants.	SGS tested and certified by NSF/ANSI 58 & 42 and FCC listed. Effective elimination of tap water risks with EPA 200 standard compliance, featuring composite filter technology for odor and chloride reduction.
Features	8-stage RO filtration with 0.0001μm membrane; 800 GPD capacity with fast 5-second water delivery; efficient 3:1 pure to drain ratio saving up to 1200% water; smart faucet; under sink tankless design; reduces PFAS.	8-stage tankless filtration; 600 GPD capacity; 2:1 pure to drain ratio; smart LED faucet with TDS monitor and filter life tracker; broad contaminant reduction including radium and radioactive substances.	8-stage tankless design; 400 GPD capacity; 2:1 pure to drain ratio; composite pre-activated and post carbon filters; coconut-shell activated carbon for improved taste and odor; reduces PFAS.
Best For	Users wanting high capacity (800 GPD) with fast water flow and water-saving 3:1 pure to drain ratio, plus advanced contaminant reduction including PFAS and smart faucet features.	Consumers seeking certified comprehensive contaminant removal including radioactive substances, with smart faucet monitoring and moderate water-saving efficiency.	Those preferring a compact tankless design with focus on taste and odor improvement, moderate capacity, and standard water-saving efficiency.

In my opinion, this Stokk Tankless Reverse Osmosis System S2 stands out because of its impressive 800 GPD fast flow capacity combined with an efficient 3:1 pure to drain ratio that saves significantly more water than competitors. Its advanced 8-stage filtration certified by NSF/ANSI 58 & 42 and FCC ensures removal of over 1000 contaminants including PFAS, making it a top choice for health-conscious users who want quick access to pure water without waiting. If you’re like me and prefer a high-performance, water-efficient system with smart faucet features, this is the better choice.

Customer Feedback on Stokk Tankless Reverse Osmosis System, 800 GPD Fast Flow Water Filter, NSF/ANSI 58&42, 8 Stage RO System, 3:1 Pure to Drain, Under Sink Tankless RO System, Smart Faucet, Reduce PFAS, S2

Overall Satisfaction

Customers generally rate the system highly, appreciating its fast flow and effective filtration with an average rating close to 5 stars.

Most Praised Features

• Fast water flow rate with 800 GPD capacity, reducing wait time significantly.
• Effective multi-stage filtration that noticeably improves water taste and quality.
• Smart faucet design offering convenience and modern aesthetics.

Common Concerns

• Installation can be challenging for some users without prior plumbing experience.
• Occasional reports of minor leaks or component fitting issues shortly after setup.

Who Loves It Most

Homeowners seeking high-capacity, efficient under-sink water filtration with advanced contaminant removal, especially those concerned about PFAS and water purity, find this system particularly appealing.

Is It Worth the Price?

Price Analysis

At $199, the Stokk Tankless RO System is competitively priced compared to similar 8-stage, high-capacity reverse osmosis systems. The 26% discount off the original $269 price makes it an affordable option for high-quality water filtration.

Value Features

• NSF/ANSI 58 & 42 Certification – Ensures proven contaminant removal, justifying trust and safety in the product.
• 8-Stage Filtration – Removes 1000+ contaminants including PFAS, providing comprehensive water purification.
• 800 GPD Fast Flow & 3:1 Pure to Drain – Offers rapid water delivery and significant water savings, reducing waste and wait time.
• Smart Faucet & Auto Flush – Maintains filter longevity and water purity, cutting down on maintenance costs and wasted water.

Vs. Competitors

Compared to other under-sink RO systems with similar certifications and capacity, Stokk offers a better water efficiency ratio and faster flow at a lower or comparable price point, making it a strong contender in its category.

Final Verdict

Given its certifications, advanced filtration, high flow rate, and water-saving features, the Stokk Tankless RO System offers excellent value for money, especially at the discounted price.