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Head-to-head buyer guide

WaterAnywhere Direct Flow, RO-DF600 vs RKIN Flash Undersink Reverse Osmosis System

Specs, prices, editor verdict, and who should buy which, compared side by side.

By Ryan · Founder
Updated Oct 10, 2026

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Quick verdict

WaterAnywhere Direct Flow, RO-DF600 (mid, $578.8) vs RKIN Flash Undersink Reverse Osmosis System (mid, $329.45). Different tools for different jobs (see the per-product details below).

Compared on 0 shared specs · same category (environment).

AMI Direct Flow tankless reverse osmosis unit, a white cabinet with a dark blue top and base and a curved blue front panel, shown alone on a white background
WaterAnywhere

Direct Flow, RO-DF600

The AMI Direct Flow is an under-sink reverse osmosis unit that filters water while the faucet runs. WaterAnywhere, AMI's distributor, lists it at $578.80.

PRICE
$578.8
View at WaterAnywhere →
RKIN Flash undersink reverse osmosis system with chrome lead-free faucet
RKIN

Flash Undersink Reverse Osmosis System

Undersink reverse osmosis usually starts around $500. The RKIN Flash lands a full RO system with a lead-free chrome faucet at $329.45, and it does it without a pump, a plug, or most of your cabinet.

PRICE
$329.45
View at RKIN →
The verdict

We have not scored these two head to head, so this page does not name a winner. The RKIN Flash Undersink Reverse Osmosis System starts at $329.45 and the WaterAnywhere Direct Flow, RO-DF600 at $578.8. The per-buyer recommendations below say who each one suits.

Who should buy which

Pick the WaterAnywhere Direct Flow, RO-DF600 if

Kitchens on municipal water with an outlet and a drain under the sink, room for a cabinet 16.5 in high and 17.5 in long, and an owner who wants reverse osmosis at the tap without a storage tank.

Skip if

You want an NSF listed system or a published contaminant test report; your supply is of unknown quality, which the manual says needs disinfection before or after the system; you want a filter life indicator, TDS display or leak shut off, none of which AMI describes; or you need longer than the store's three month warranty.

Pick the RKIN Flash Undersink Reverse Osmosis System if

Homeowners who want plumbed-in reverse osmosis at the lowest credible price and are comfortable with a weekend DIY install under the sink.

Skip if

You rent or cannot modify plumbing (RKIN's countertop units exist for exactly that), or you buy on independently confirmed certification listings, where Boroux leads this category.

Go deeper

FULL REVIEW
Read the WaterAnywhere Direct Flow, RO-DF600 review →
FULL REVIEW
Read the RKIN Flash Undersink Reverse Osmosis System review →

Frequently asked

Which is better, the WaterAnywhere Direct Flow, RO-DF600 or the RKIN Flash Undersink Reverse Osmosis System?

We have not scored these two head to head, so this page does not name a winner. The RKIN Flash Undersink Reverse Osmosis System starts at $329.45 and the WaterAnywhere Direct Flow, RO-DF600 at $578.8. The per-buyer recommendations below say who each one suits.

How much do they cost?

WaterAnywhere Direct Flow, RO-DF600: $578.8. RKIN Flash Undersink Reverse Osmosis System: $329.45. Prices are verified against the manufacturer; check the live links for current pricing.

Who should buy which one?

WaterAnywhere Direct Flow, RO-DF600: Kitchens on municipal water with an outlet and a drain under the sink, room for a cabinet 16.5 in high and 17.5 in long, and an owner who wants reverse osmosis at the tap without a storage tank. RKIN Flash Undersink Reverse Osmosis System: Homeowners who want plumbed-in reverse osmosis at the lowest credible price and are comfortable with a weekend DIY install under the sink.

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