Best COSTWAY Reverse Osmosis Systems: 3 Models Compared

Quick picks

Our 3 picks

1 Best overall

COSTWAY 600 GPD Tankless RO System

Best for: tight under-sink spaces and alkaline water needs

Filtration Stages

8

Capacity (GPD)

600

Design

Under sink, tankless

Pure to Drain Ratio

2:1

Filtration Type

Reverse osmosis, alkaline

Contaminants Removed

PFOA, lead, fluoride, TDS

View on Amazon: COSTWAY 600 GPD Tankless RO System Affiliate link

This tankless under-sink unit produces 600 gallons per day using an 8-stage alkaline filtration process. It features a 0.0001µm membrane to remove lead, fluoride, and PFOA. The compact footprint saves space under your sink. A smart LED faucet displays real-time TDS levels and filter status. It includes auto-flushing to extend filter life. This system suits you if you want mineral-enhanced water quality without a storage tank.

Pros

• 8-stage filtration with alkaline filter for improved taste
• Compact tankless design saves 70% of under-sink space
• Smart LED faucet shows real-time TDS and filter status
• Auto-flushing feature supports longer filter life

Cons

• 600 GPD capacity is lower than the 800 GPD model on this list
• Requires under-sink installation, limiting placement options
• No mention of a dedicated drain line connection in specifications

Good fit if

• You need a compact system that fits in tight under-sink cabinets
• You want real-time water quality monitoring via the faucet display
• You prefer alkaline water for better taste and mineral content

Skip if

• You require a countertop unit for easy relocation
• You need the highest available flow rate of 800 GPD
• You prefer a system with a large storage tank for buffer capacity

Verdict: COSTWAY 600 GPD Tankless RO System offers solid filtration and space-saving design for homeowners who value real-time water quality monitoring and alkaline benefits.

2 Best premium

COSTWAY 800 GPD Tankless RO System

Best for: high-flow tankless under-sink use

Filtration Stages

8

Capacity (GPD)

800 GPD

Design

Under sink, tankless

Pure to Drain Ratio

2:1

Filtration Type

Reverse osmosis, alkaline

Contaminants Removed

Lead, PFOA, fluoride, TDS

View on Amazon: COSTWAY 800 GPD Tankless RO System Affiliate link

This tankless under-sink system delivers 800 GPD through an 8-stage alkaline filtration process. The 0.0001µm membrane reduces lead, PFOA, fluoride, and TDS. A smart LED faucet shows real-time water quality and filter status. The compact design saves 70% of cabinet space. The 2:1 pure-to-drain ratio optimizes water use. It suits kitchens needing high flow and clear quality monitoring.

Pros

• 800 GPD tankless capacity
• 8-stage alkaline filtration
• Smart LED faucet with TDS display
• Compact 15.5-inch height

Cons

• Requires under-sink installation
• No mobile app connectivity
• Limited to alkaline filtration only

Good fit if

• You need high daily water output
• You want real-time TDS monitoring
• You have limited under-sink space

Skip if

• You prefer countertop placement
• You need app-based control
• You want a 600 GPD model

Verdict: COSTWAY 800 GPD Alkaline RO System offers high flow and clear quality tracking for space-constrained kitchens. It fits users who prioritize tankless efficiency and visible water metrics.

3 Best budget

COSTWAY Countertop RO Filter

Best for: renters and portable hydration needs

Filtration Stages

5

Design

Countertop

Pure to Drain Ratio

4:1

Filtration Type

Reverse osmosis, UV

Installation Type

Countertop

Features

UV light treatment

View on Amazon: COSTWAY Countertop RO Filter Affiliate link

This countertop reverse osmosis system uses a 5-stage filtration process including a 0.0001 μm RO membrane and UV light treatment. It features a touch screen with volume options and a 4:1 pure-to-drain ratio. The unit measures 17.5 by 7.5 by 16 inches and requires no plumbing. It suits renters or those needing portable hydration without under-sink installation.

Pros

• 5-stage filtration with UV light treatment
• 0.0001 μm RO membrane reduces 95%+ TDS
• 4:1 pure-to-drain water ratio
• Touch screen with 80/180/300/500 ml options
• Tool-free filter replacement

Cons

• Countertop design requires counter space
• No tankless high flow rate like 800 GPD models
• Manual volume selection instead of continuous flow

Good fit if

• You need a portable water purifier for an RV or office
• You cannot install an under-sink system due to rental restrictions
• You want UV light treatment for additional purification

Skip if

• You need high-volume water for cooking or filling large pots
• You prefer a tankless system with higher GPD output
• You want a compact under-sink unit to save counter space

Verdict: COSTWAY Countertop RO Water Filter fits users who need portable, UV-treated water without plumbing. It is a practical solution for small spaces or temporary setups.

Specifications side by side

COSTWAY Reverse Osmosis Systems Compared

The COSTWAY lineup divides into two clear groups: tankless under-sink systems and portable countertop filters. You should choose based on your installation type and capacity needs. The tankless models, including the COSTWAY 600 GPD and 800 GPD systems, fit under sinks with compact dimensions around five inches wide. Both feature alkaline filters for improved taste.

If you need a portable solution, the COSTWAY Countertop RO Filter offers UV treatment without plumbing. This model suits renters or those with limited space. Compare the GPD ratings to match your household flow requirements. The 600 GPD unit ranks best overall for tight spaces, while the 800 GPD version provides higher output. Select the model that aligns with your specific water quality goals.

Where COSTWAY Fits Your Needs

COSTWAY’s range targets specific installation types rather than offering a broad spectrum. You can choose between compact under-sink units or a portable countertop filter. The tankless models, measuring roughly 5.5 inches wide, fit tight spaces while delivering 600 to 800 gallons per day. Both include alkaline filters for improved taste. The countertop option provides a no-plumbing solution for renters or temporary setups. You will not find large capacity tank systems or smart app connectivity in this lineup. This brand suits users who need straightforward filtration without complex integration.

Choosing the Right System

1. Match Capacity to Flow

   Select your daily water volume needs first. The 600 GPD model provides steady output for average households. The 800 GPD unit delivers faster refill rates for high-demand kitchens. Both tankless designs lack storage tanks, so flow rate depends directly on membrane capacity. Higher GPD means quicker glass filling but also higher wastewater production. Check your faucet flow requirements. If you entertain often, the 800 GPD option reduces wait times. For standard use, the 600 GPD system suffices. Always verify that your supply line pressure supports the chosen capacity for optimal performance.

2. Check Under-Sink Dimensions

   Measure your cabinet space before buying. The tankless models share a narrow width of 5.5 inches. This slim profile fits most standard under-sink areas. However, height and length vary slightly. The 600 GPD model is 15.5 inches tall and 15 inches long. The 800 GPD version is 15.5 inches tall but 14.5 inches long. Ensure you have enough clearance for filter changes. Leave room for connections and maintenance access. The countertop model requires counter space, measuring 17.5 inches long. Verify your available footprint matches the system's physical specs to avoid installation issues.

3. Decide on Installation Type

   Choose between permanent under-sink units or portable filters. Under-sink systems require plumbing connections and professional or skilled DIY installation. They offer higher capacity and better integration. The countertop filter needs no plumbing. It sits on your counter and connects to the faucet. This suits renters or those without access to under-sink space. It is also ideal for temporary setups. Consider your lease terms and mobility needs. Permanent systems provide consistent high-volume output. Countertop units offer flexibility and easy removal. Pick the type that matches your housing situation.

4. Evaluate Alkaline Benefits

   Determine if you want enhanced pH levels. Both tankless models include alkaline filters. These add minerals to raise water pH. This may improve taste for some users. The countertop model uses UV treatment instead. It focuses on purification without mineral addition. If you prefer neutral pH water, the countertop option avoids alkaline additives. If you seek alkaline benefits, choose either tankless system. Note that alkaline filters require periodic replacement. Factor this into your long-term maintenance plan. Decide whether mineral enhancement is a priority for your drinking water routine.

5. Consider Portability Needs

   Assess how often you move systems. The countertop filter is fully portable. You can unplug it and move it easily. This is useful for seasonal homes or shared spaces. The under-sink models are fixed installations. They remain connected to your plumbing. Moving them requires disconnecting lines and refilling. If you travel frequently or rent short-term, the countertop unit offers convenience. For permanent homes, the under-sink systems provide better performance. Think about your lifestyle and housing stability. Portability adds flexibility but may limit flow capacity compared to plumbed systems.

Frequently asked questions

See also

• costway alkaline ph ro water vs countertop reverse osmosis water
• costway 600 gpd tankless ro vs 800 gpd tankless ro
• best reverse osmosis systems for iron
• best COSTWAY sofas