See the purity, trust the technology. A tankless under-sink system that delivers ultra-pure, clean, refreshing water on demand—built for the Florida Keys lifestyle in Marathon.
The System Itself
Designed for Marathon living in the Florida Keys: the whole system fits under your sink and connects with quick-connect fittings. Four quick-change twist cartridges provide the four filtration stages, with a UV chamber inline. There’s no bulky storage tank, so water is purified on demand instead of sitting and waiting.
The first cartridge captures rust, dirt, sand, and sediment—especially helpful for Keys well/cistern setups.
Carbon block media that reduces chlorine, odors, color, and chemicals before the membrane—great for municipal or well/cistern setups in Marathon.
The heart of the system—rejects dissolved solids and heavy metals and sends the concentrate to the drain (ideal for many Marathon water sources).
The final cartridge polishes the water and adds beneficial minerals back for a balanced pH—great for everyday drinking in Marathon.
Filtration Stages
Each stage handles what the one before it left behind—helpful for Marathon’s mix of municipal and well/cistern setups where sediment control matters. UV is step four, and it’s not filtration at all; it treats what filters can’t catch.
Removes rust, dirt, sand, and large particles—ideal for Keys sediment issues.
Reduces chlorine, odors, color, and chemicals from your Marathon water.
Removes up to 99% of dissolved solids, heavy metals, and more—helping you get cleaner water in Marathon.
Kills 99.99% of bacteria, viruses, and microorganisms.
Adds beneficial minerals for a balanced, healthy pH—great for everyday hydration in Marathon.
Four filtration stages plus UV sterilization. Steps 1 to 3 and 5 are the four filtration stages; step 4 is the built-in UV lamp (disinfection, not filtration). It’s included in the price on every system we install in Marathon.
Pricing
The systems are identical—the difference is how many we install on the same visit in Marathon. Every unit includes UV sterilization and professional installation.
1 UnitInstalled
Regularly $2,000 - you save $1,005
The standard install, and the right fit for a kitchen sink in most Marathon homes.
2 UnitsInstalled
A lower price per unit on a two-system install for your Marathon property
Great for a kitchen and wet bar—perfect for Keys homes with guest space.
3 or MoreInstalled
Our lowest per-unit price in Marathon
Ideal for larger Marathon homes, multi-unit properties, and light commercial spaces across the Keys.
All prices are installed and include UV sterilization, with no hidden fees. Not sure how many you need? We’ll walk your Marathon property with you during the visit.
Technical Specifications
The SimPure ROULP-3012-400-T1, from the T1-400 series. A tankless build that produces up to 400 gallons a day on demand, so the water is made when you draw it rather than stored.
400 GPD
Production rate
1.5:1
Pure-to-drain ratio
1,057 gal
Per full cartridge set
99.99%
Maximum TDS reduction
The T1-400 series tankless under-sink reverse osmosis system for Marathon.
Typically 95% and up to 99.99%, bringing 200–500 PPM tap water to near 0 PPM, or below 25 PPM—results vary across Marathon sources.
The lamp operates automatically based on water flow pressure, and can be adjusted.
Keeps water fresh, saves under-sink space, and helps prevent secondary contamination—especially helpful in warm, humid Marathon kitchens.
One gallon of wastewater for every 1.5 gallons of purified water produced.
One full cartridge set is roughly the equivalent of 8,000 bottles—less plastic headed to the Keys.
One Unit, Installed
$995
Installed
Regularly

Unit, all four cartridges, faucet, fittings & all parts—ready for your Marathon kitchen.

The built-in UV lamp is included—no upgrade needed.

Fitted under your sink and commissioned by pros familiar with Marathon’s municipal and well/cistern setups.

We test your water before and after—so you can see the difference in your Marathon home.

No surprises—one low price includes everything for Marathon homes.

Lower per-unit pricing when we install two or more—perfect for Marathon homes with multiple sinks.
Independent Testing
You don’t have to take performance on faith. The system has been tested by an independent laboratory against the recognised standard for reverse osmosis drinking water systems.
Testing covers the removal of over 99.99% of more than 1,000 contaminants, including total dissolved solids such as fluoride, nitrates and nitrites; PFAS, PFOA and PFOS; heavy metals such as lead and arsenic; and chloride.
Made by SimPure
SimPure is based in Seattle, Washington and has served the USA since 2006, with trained water specialists available for product support.
Reduction performance varies with source water and household usage—municipal vs. well/cistern can differ around Marathon. We test your water on the visit so you know what you’re starting from.
Perfect For
Point-of-use installation means the water you drink and cook with in Marathon is the water that gets purified.
Cleaner Water. Better Living. In the Keys.
Installed by a Florida plumbing company that understands Keys conditions—and stands behind the work.
Built with premium materials for reliable performance in Marathon’s salt air.
The built-in UV lamp is included in the price on every unit we install in Marathon.
We stand behind our products and the quality of our work in Marathon.
Join homeowners across Marathon and Monroe County who choose Mr. Pure Water.
Product Assurances
Better-tasting, odor-free water for drinking, cooking, and everyday use in Marathon and the Florida Keys.
Tankless purification as you draw—no storage tank, no waiting, and less worry in Marathon’s warm, humid climate.
Built-in UV helps eliminate bacteria, viruses, and microorganisms—a smart extra layer for Keys well/cistern water.
The Mr. Pure Water Under-Sink Reverse Osmosis System with UV Sterilization is a tankless point-of-use system that fits neatly under your sink with quick-connect fittings—great for Marathon homes in a tropical, coastal climate. Cold water enters a PP sediment cartridge that catches rust, dirt, sand and large particles, then a CTO carbon block that takes out chlorine, odors, colors and chemicals. The reverse osmosis membrane removes up to 99% of dissolved solids and heavy metals, sending the concentrate to the drain at a 1.5:1 pure-to-drain ratio. A built-in UV lamp then kills 99.99% of bacteria, viruses and microorganisms—the one thing a filter cannot catch—operating automatically on water flow pressure. An alkaline and mineral stage finishes the water, putting beneficial minerals back for a balanced pH. Five stages in all—PP, CTO, RO, UV and alkaline—producing up to 400 gallons a day on demand, with no bulky storage tank to hold water, take up space or invite secondary contamination.
One Unit, Installed in Marathon
$995
Installed
Regularly