Cahaba Water Co.
Sizing and treatment level

Two decisions. One properly sized system.

Every whole-home system we build answers two separate questions. What does your water need treated? And how much water does your house use at once? Two different questions, each with its own answer, and we measure both before we build anything.

Decision one
Treatment level —
what your water needs
Decision two
System size —
what your home demands
Set by measurement
Both answers come from
readings at your house
Whole-home price
Quoted after sizing
The two decisions

Two tracks. They run beside each other, and each reaches its own answer.

One track decides what gets treated. The other decides how big the system is.

A simpler way to buy water treatment: two questions, answered separately, in front of you. Rolling them into one package price is how a house ends up carrying treatment nobody asked for, or how the right treatment ends up choked by a system that is too small.

Decision one

Treatment level

What does this homeowner want or need treated?

  1. 01
    Start with the water and the goals

    Three things set the scope. What Central Alabama Water (formerly Birmingham Water Works) publishes for your supply. What you can taste or smell. And what you actually want changed.

  2. 02
    Test where testing decides something

    Hardness is the clearest example. We test hardness before recommending a softener, and the measured number is what settles it.

  3. 03
    Choose the level your water calls for

    Three levels: Cahaba Whole Home Essential, Cahaba Whole Home Complete or Cahaba Whole Home Signature. The level describes scope: how much of the house gets treated, and for what.

This track reads your published water report, what you can taste and smell, and the goals you have for the house.

Decision two

System size

How much water must this home handle at peak demand?

  1. 01
    Measure the house, not the listing

    We measure the service line, the pipe that brings water in from the street. Then we count the fixtures that really move water: body sprays, soaking tubs, laundry, dishwasher.

  2. 02
    Take real pressure readings

    We take static and dynamic pressure at the house. Dynamic is the reading taken while water is moving. It tells us what happens when three things run at once.

  3. 03
    Size to peak demand

    Four sizes: S Standard Flow, M Enhanced Flow, L High Flow or XL Estate Flow. We pick one against what the build needs. That includes the backwash rinse that cleans the filter media.

This track reads the service line, the fixture count and the pressure at the house. A size is a plumbing answer to a plumbing question.

Treatment level is about what gets treated. Chlorine taste and odor at every tap. Hardness, where testing and your own goals call for a softener. A drinking-water system at the kitchen sink. And UV as an extra barrier, where it fits.

System size is about how much water moves through. The equipment has to pass your peak demand while staying out of the way of your plumbing. Size it to the flow your house actually creates and the shower stays strong, the media gets the flow it needs, and you pay for capacity the home will use.

The two axes

Three treatment levels. Four sizes. Twelve legitimate systems. Whole home

Treatment level down the side, system size across the top, and twelve correct answers.

Read down for what gets treated. Read across for how much water the system passes. Every treatment level comes in every size, and a finished build is named for both. A Cahaba Whole Home Complete at Enhanced Flow is written Cahaba Whole Home Complete ‑ M.

Treatment level down the side · system size across the top
SStandard Flow MEnhanced Flow LHigh Flow XLEstate Flow
Cahaba Whole Home Essential Carbon filtration at every tap. Add a softener where testing calls for one, and a drinking-water system whenever you want it. Cahaba Whole Home Essential ‑ S Cahaba Whole Home Essential ‑ M Cahaba Whole Home Essential ‑ L Cahaba Whole Home Essential ‑ XL Example A — below
Cahaba Whole Home Complete Carbon filtration at every tap, a softener if your water needs one, and a Cahaba under-sink RO. Cahaba Whole Home Complete ‑ S Cahaba Whole Home Complete ‑ M Cahaba Whole Home Complete ‑ L Cahaba Whole Home Complete ‑ XL
Cahaba Whole Home Signature The most complete system we build, designed around your house. The widest set of options, configured to what your water and your goals call for. Cahaba Whole Home Signature ‑ S Example B — below Cahaba Whole Home Signature ‑ M Cahaba Whole Home Signature ‑ L Cahaba Whole Home Signature ‑ XL

Every cell in this grid is a finished system. Twelve combinations, each one correct for the house it belongs to. Your two readings pick the cell.

The price follows the build, and the build follows the measurements: Quoted after sizing.

The two marked cells are the two homes described below. They sit in opposite corners. That is the shortest way to show that the two decisions are independent.

We size your system from your home's actual water demand, measured at the house.

Cahaba Water Co. — how we quote
A single black treatment tank with a control valve head standing beside a water heater in a garage, with copper piping above.
One tank, sized right A smaller package is not a lesser one. Representative equipment — how many tanks you need follows measured flow and measured hardness, not the square footage of the house.
Two houses

The big house takes the small package. The small house takes the big one.

A big house can need our simplest system. A small house can need our most complete one.

These two cases break the assumption, and both of them are ordinary Birmingham houses.

ASix bathrooms, one complaintWhole home

A big house with six bathrooms, where the only complaint is the chlorine taste. That house may need Cahaba Whole Home Essential at XL Estate Flow. It really does move a lot of water at once. Several showers can run alongside the laundry and the dishwasher, so the size has to be large. But the treatment goal is narrow, so Essential is the right level and the budget goes into flow capacity, where this house will actually use it. Cahaba Whole Home Essential ‑ XL

BTwo bathrooms, everything treatedWhole home

A small house with two bathrooms, where the owner wants everything: filtered water at every tap, softer water, our best drinking-water system, and UV. That house may need Cahaba Whole Home Signature at S Standard Flow. The flow demand is modest. The house creates a peak that S Standard Flow carries comfortably. But the treatment list is the long one, so the level goes all the way up while the size stays where the plumbing puts it. Cahaba Whole Home Signature ‑ S

Both builds are real, and both are priced the same way as every other cell in the grid: Quoted after sizing.

A larger system is the right system exactly when your home's flow demand calls for it.

Cahaba Water Co. — how we size
What sizing considers

A size is an answer to a plumbing question.

Everything we measure or count before we pick a size.

These are the inputs. Some we measure on site and some we count. The ones that decide the size come from the plumbing itself.

  • The service line, the pipe that brings water in from the street
  • The number of bathrooms, and the fixture count
  • Showers that can run at the same time
  • Multiple showerheads or body sprays
  • Large soaking tubs
  • Laundry and dishwasher demand
  • Other fixtures that move a lot of water
  • Static pressure, measured at the house
  • Dynamic pressure, measured while water is moving
  • Peak GPM, which is gallons per minute at the busiest moment
  • The flow the treatment media needs to work
  • How much water the valve can pass
  • The backwash rinse that cleans the media

We size whole-home systems from actual water demand. Square footage, home value, ZIP code and the number of people in the house give useful context, and the measurements decide it. Two homes of the same square footage can have completely different peak demand, depending on the service line, the fixtures and the pressure at the meter. Your size comes from the readings we take at your house.

What we publish about size
What is documented, and where the claim stops

The inputs above, in full, before you agree to anything

The size we arrive at, and the readings that produced it

Your whole-home price, quoted once the house is measured and confirmed before anything is scheduled, because the price follows the build and the build follows the measurements

Flow breakpoints for S, M, L or XL stay with the sizing visit until those numbers are locked. A number we would have to correct later is worse than no number at all

The method itself is published too. Carbon capacity follows your peak flow, softening follows your measured hardness, and boosting follows a pressure test. See how we size systems.

A separate decision again

Drinking water is its own choice, at its own published price. Drinking water

Four under-sink systems, each with a published price, each sold on its own.

Each one installs at a single tap, carries a fixed installed price, and stands on its own. Take one by itself, or pair it with a whole-home system at any treatment level and any size.

The four drinking-water systems, side by side

Cahaba Pure 50

ESSENTIAL
Two sink cabinets side by side: one holding a reverse osmosis system with a pressurized storage tank, the other holding a compact tankless unit.
Illustration — the same cabinet, both ways. A tank platform on the left, tankless on the right. The difference is the space the tank takes, not the tap it feeds.

Reverse osmosis drinking water at one tap, at our lowest installed price.

For homeowners who mainly want better drinking water, with normal household use and enough incoming pressure to run it.

IAPMO R&T certifies this configuration to NSF/ANSI 58 and CSA B483.1, including PFOA and PFOS reduction.

$995installed

Cahaba Performance 75

PERFORMANCE

More water per day, with boosted RO performance.

For homes that want more production, or where the pressure coming in needs support.

The manufacturer identifies the membrane and the storage tank as NSF certified. We do not claim complete-system certification for this platform.

$1,095installed

Cahaba Signature 75

SIGNATURE

Our premium traditional-tank RO system.

For homeowners who want the top traditional-tank RO platform Cahaba offers.

The storage tank is identified as NSF certified, not the complete system. We do not claim complete-system certification for this platform.

$1,295installed

Cahaba Slim 800

TANKLESS

High-output RO with no storage tank under the sink.

Choose Slim 800 for cabinet space and direct-flow production. It is an alternative to the traditional-tank systems, at the same installed price as Cahaba Signature 75.

We publish no certification claim for this platform.

$1,295installed
How we talk about the ladder
What is documented, and where the claim stops

A higher rung means a different platform at a different price, described in the words its own documentation supports

Certification is stated per product, at the level it is actually documented: complete system, component, or not published

A higher production figure does not mean greater contaminant reduction

More stages does not mean better treatment

Tankless does not mean cleaner or purer water

A claim documented for one product is never repeated for another

Manufacturer detail, without pricing attached, is published on the equipment page.

Compare all four in full

Questions

Questions we get about this.

Does a bigger house need a higher treatment level?
Treatment level and system size are two separate decisions. Treatment level answers what you want or need treated. System size answers how much water your house has to handle at once. A big house with six bathrooms, where the only complaint is the chlorine taste, is often the right fit for Cahaba Whole Home Essential at an XL Estate Flow size: a large size, matched to a focused treatment goal.
Is Cahaba Whole Home Signature better than Cahaba Whole Home Essential?
It is broader, not better. Cahaba Whole Home Signature is the most complete system we build, with the widest set of options, and each build carries the options that home calls for. If carbon filtration at every tap meets a home's goals, Cahaba Whole Home Essential is the right system for that home, and it is the one we recommend.
What do S, M, L and XL mean?
They are sizes: S Standard Flow, M Enhanced Flow, L High Flow and XL Estate Flow. They describe how much water the system is built to pass at once. We set the size during the sizing visit, from the service line, the fixture count, measured static and dynamic pressure, and the peak demand the home actually creates. The breakpoints between sizes belong to that visit rather than to a published chart, because your readings decide it.
Do you size a system from square footage?
We size from the plumbing itself. Square footage, home value, ZIP code and the number of people living there give useful context, and the measurements settle it. Two homes of the same square footage can have very different peak flow demand, depending on service-line size, fixture count and pressure.
What does a whole-home system cost?
Quoted after sizing. The price follows the build and the build follows the measurements, so you get a number that belongs to your house, confirmed before anything is scheduled. Our under-sink drinking-water systems are published at a fixed installed price: Cahaba Pure 50 at $995 installed, Cahaba Performance 75 at $1,095 installed, and Cahaba Signature 75 and Cahaba Slim 800 at $1,295 installed.
Is the biggest system the best one?
The best system is the one your flow demand calls for. A larger size is right exactly when the house creates the peak to justify it. An oversized system adds cost, and it leaves what the water is treated for exactly where it was, because that is the other decision entirely.

Both decisions, in one visit

We measure the house and test what testing decides. Then we give you the treatment level and the size separately, each with the readings behind it, and we confirm the final price before scheduling.

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Cahaba Water Co.Sized to your house
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