What this does: it treats the water you drink and cook with, at one tap in your kitchen.
The Cahaba Signature 75 is the top of our storage-tank line. RO is short for reverse osmosis: water is pushed through a very fine membrane, and the treated water waits in a small tank under your sink. This one runs on a high-efficiency RO platform — a 75-GPD membrane, booster-assisted operation, and an internal recirculation design built to send far less water to the drain.
Under-sink, single visit. Nothing is added to your main water line.
This is our efficiency system. The same kitchen tap and the same ready-when-you-are tank, on a platform designed to keep far more of the water it takes in.
Cahaba Signature 75 uses a high-efficiency RO platform. It combines a 75-GPD membrane, booster-assisted operation and an internal recirculation design intended to recover substantially more feed water than a conventional residential RO system.
Instead of sending concentrate straight to the drain, the platform recirculates it back through the membrane. The manufacturer describes the result as a 99.9% recovery design — the reason this system exists.
Manufacturer-describedTDS is total dissolved solids — the minerals and salts carried in solution that give water much of its taste. The manufacturer rates this membrane at up to 99% TDS rejection.
Manufacturer-ratedThe manufacturer describes the housings as heavy-duty glass-filled polypropylene — a stiffer, more dimensionally stable material than plain plastic, which is what you want on a component that lives under a sink for a decade.
Manufacturer-describedHow to read those three figures. Manufacturer performance ratings are shown as manufacturer specifications, not as third-party certification claims unless separately documented. Certification wording on this page appears further down, in the certifier's own words.
You book it, a licensed plumber installs it, and the price you were quoted is the price on the invoice. Here is everything that number carries.
Equipment, labor and a 12-month workmanship warranty in one published figure, confirmed before anything is scheduled
Standard installation is included — an accessible cold-water shut-off under the sink, an existing faucet hole or a countertop we can drill, a standard trap, and room in the cabinet. Subject only to unusual site conditions confirmed before scheduling
A single under-sink visit by a licensed Alabama plumbing contractor. Nothing is added to your main water line
Yours to service anywhere — a standard platform from an established manufacturer, with consumables available from water-treatment suppliers
Priced over the phone — we confirm your number and book the install, usually the same day you ask
Birmingham's water meets every federal and state standard. The Signature 75 is about taste, convenience at the tap, and how much water the system keeps while it works.
Read across, not up. A higher price buys different hardware and a different design, and every one of the four is a system we are glad to install.
Three of them form a ladder by price and platform. The fourth is a tankless alternative that happens to cost the same as the top of it. Each carries its own documentation, quoted below in the words the paperwork actually uses.
Positioning: premium reverse-osmosis drinking water at our lowest installed price.
Choose it for: better drinking water in a home with normal household use and enough incoming pressure — and for the strongest certification file on the ladder.
Documented: IAPMO R&T certifies this configuration to NSF/ANSI 58 and CSA B483.1, including PFOA and PFOS reduction.
Positioning: more production and boosted RO performance.
Choose it for: higher production, or a home where incoming pressure needs help.
Documented: The manufacturer identifies the membrane and the storage tank as NSF certified. We do not claim complete-system certification for this platform.
Positioning: our high-efficiency traditional-tank RO.
Choose it for: the top traditional RO platform Cahaba offers — a 75-GPD membrane, booster-assisted operation, and an internal recirculation design built to recover substantially more feed water.
Documented: The storage tank is identified as NSF certified. We do not claim complete-system certification for this platform.
Positioning: high-output RO without the storage tank. A premium alternative at the same price as the Signature 75.
Choose it for: cabinet space and direct-flow production. Tankless is a decision about the cabinet and the production rate.
Documented: no certification is documented for this platform yet. When one is, it will appear here in the certifier's words.
Every row is a fact from our product record. The last column is the only certification wording each product is allowed to carry.
| System | Rung | Production | Booster pump | Storage | What is documented | Installed |
|---|---|---|---|---|---|---|
| Cahaba Pure 50 | ESSENTIALRO ladder | 50 GPD | No | Approximately 4-gallon metal tank | IAPMO R&T certifies this configuration to NSF/ANSI 58 and CSA B483.1, including PFOA and PFOS reduction. | $995 |
| Cahaba Performance 75 | PERFORMANCERO ladder | 75 GPD | Yes | NSF-certified 3.0-gallon tank | The manufacturer identifies the membrane and the storage tank as NSF certified. We do not claim complete-system certification for this platform. | $1,095 |
| Cahaba Signature 75 | SIGNATURERO ladder | 75 GPD | Yes | NSF-certified 3.0-gallon tank | The storage tank is identified as NSF certified. We do not claim complete-system certification for this platform. | $1,295 |
| Cahaba Slim 800 | TANKLESSRO ladder | 800 GPD | Not documented | None — tankless | No certification documented yet. | $1,295 |
What the extra $200 buys. The Cahaba Performance 75 and the Cahaba Signature 75 both include a booster pump, so the pump is not the upgrade — it is what separates the Pure 50 from the Performance 75. The Signature 75 steps up to a high-efficiency RO platform: an internal recirculation design that returns concentrate to the membrane rather than the drain, and heavier-duty construction around it. That is the $200.
Production figures are manufacturer ratings rather than measured output in your house, and they describe flow rather than reduction. Treat a GPD number as a measure of how fast a system makes water.
Every line below is something we can point at in a document — our product record, or the manufacturer's own published specification, labeled as such.
Nominal means the rating the maker publishes rather than what we measured in your kitchen. The Signature 75 is built on a Hydrotech / Aqua Flo high-efficiency RO platform, and every figure attributed to the manufacturer is printed here the way the manufacturer states it.
A stage count is not published for this platform, and it is a poor proxy for treatment quality in any case — what matters is the membrane, the pressure behind it, and what the paperwork documents. Ask us for the specification sheet and we will send what the manufacturer publishes.
Manufacturer ratings and third-party certifications are two different kinds of evidence, and this page keeps them apart on purpose. Here is the exact certification line for the Signature 75.
The storage tank is identified as NSF certified, not the complete system. We do not claim complete-system certification for this platform.
The recovery, rejection and construction figures above are manufacturer specifications — published here with the manufacturer named as their source, and labeled manufacturer-rated or manufacturer-described wherever they appear
Where complete-system certification is the deciding factor, the Cahaba Pure 50 is the one to look at: IAPMO R&T certifies that configuration to NSF/ANSI 58 and CSA B483.1, including PFOA and PFOS reduction
A certified component is not a certified system, and we write the narrow line rather than the flattering one
Ask us for the paperwork and you get the paperwork: the tank listing, the manufacturer's specification sheet, and a plain account of which is which.
Which drinking-water system goes under your sink is a third decision again. Keeping the three apart is how a house gets sized and treated correctly, so it is worth two minutes.
Two things are called Signature. Drinking water Cahaba Signature 75 is this page. It sits under your kitchen sink, and the price is $1,295 installed. Whole home Cahaba Whole Home Signature is a treatment level for the whole house. Quoted after sizing. The two share a word and nothing else, which is why we always write the full name.
What does this home want or need treated? Chlorine taste and smell. Hard water, where testing justifies it. One more barrier such as UV, where it earns its place. This is a question about your goals and your water.
How much water does this home move at once? The pipe that brings water in from the street, the bathroom count, showers running together, tubs, laundry, and the pressure we measure. This is a question about plumbing, answered by measurement.
Which system goes under the kitchen sink. That is this page's question, and it is separate from both of the others. The Signature 75 sits happily behind any treatment level and any size.
Valid buildExample shown aboveEvery treatment level is available in every size.
Twelve real builds. A finished build is named for both answers at once — for instance, “Cahaba Whole Home Complete ‑ M”. The right cell is wherever your goals and your measured demand land, and the two examples below sit at opposite ends to make that plain.
A big house with six bathrooms, where the only complaint is the chlorine taste. Treatment level: Cahaba Whole Home Essential. Size: XL, Estate Flow. Our simplest treatment at our largest size, and entirely correct.
A small house with two bathrooms, where the owner wants everything: filtered water at every tap, softer water, our premium drinking-water system, and UV. Treatment level: Cahaba Whole Home Signature. Size: S, Standard Flow. Our fullest treatment at our smallest size, and also entirely correct.
Sizing comes from a look at your own plumbing and the pressure we measure, and treatment level comes from your goals and your water. Whole-home pricing is quoted after sizing, so every house gets a number built for its own demand.
Every Cahaba drinking-water price is published on one page, next to the certification wording each system carries. Plenty of people read this page, decide the Pure 50 or the Performance 75 is the better fit for their kitchen, and we are glad to install either.
No appointment, no sales visit. We confirm your price and book the install — usually the same day you ask.
Ask for the documentation when we call. You will get the tank listing and the manufacturer's specification sheet, with each one labeled for what it is.
Cahaba Water Co.