Phoenix tap water typically measures 500 to 800 parts per million of total dissolved solids, depending on the source and the season. The EPA secondary guideline is 500 ppm. That TDS number reflects everything dissolved in the water: the calcium and magnesium that make it hard, the chloramine the city uses for disinfection, and trace levels of fluoride, nitrates, arsenic, and other compounds the treatment plant does not fully remove. A reverse osmosis system forces water through a semipermeable membrane under household pressure, and the membrane rejects 95 to 99 percent of those dissolved solids. What reaches your glass has a TDS in the single digits.
A standard under-sink RO unit runs four or five stages. Water enters a sediment pre-filter first, then passes through a carbon block that strips chloramine before it can degrade the membrane. The membrane itself does the heavy filtration, blocking dissolved solids along with lead, arsenic, fluoride, nitrates, PFAS, and most pharmaceutical traces. Filtered water collects in a small pressurized storage tank, usually two to four gallons, and flows through a final carbon post-filter to a dedicated faucet mounted at your sink. Some systems add a post-filter stage after the tank, such as a remineralizer that puts a controlled amount of calcium and magnesium back into the water for taste and alkalinity. Reject water carrying the concentrated contaminants drains through a line connected to the existing sink drain.
If your home runs hard water at 12 to 20 grains per gallon, which covers most of the Valley, a water softener upstream of the RO protects the membrane from mineral scale and extends its service life. The RO removes the sodium the softener adds, so the two systems handle different problems and complement each other. Our water treatment guide covers when you need one, the other, or both. Call 602-560-8989 for a free estimate on a system sized to your household.
What We Handle
Our Process
Test Your Water
We measure TDS, hardness, and water pressure at your kitchen sink. Those numbers tell us what the membrane needs to handle and whether your plumbing can support the system without modifications. If you already have a water softener or other filtration, we factor that into the staging so the equipment works together rather than at cross purposes.
Size and Install
We recommend a system based on your water quality results and your household's drinking water volume. Installation goes under the kitchen sink: sediment pre-filter, carbon stage, membrane housing, storage tank, drain line connection, and a dedicated faucet through the countertop or sink deck. We check every fitting for leaks and run the initial flush cycle the membrane requires before use.
Confirm the Output
We test the filtered water with a TDS meter so you can see the before and after numbers for yourself. We walk you through the filter replacement schedule, typically six to twelve months for the pre-filters and carbon stages, two to three years for the membrane. You get a flat-rate price for the installation and a maintenance plan option if you want us to handle the filter changes going forward.
Frequently Asked Questions
The membrane blocks 95 to 99 percent of total dissolved solids. In practical terms for Phoenix tap water, that includes the chloramine the city uses for disinfection, fluoride, nitrates, lead, arsenic, sodium, PFAS compounds, and most pharmaceutical residues. It also removes the calcium and magnesium that cause hard water, but only at the one faucet the RO serves. If you want to address hardness for the whole house, fixtures, water heater, showerheads, that is what a water softener handles.
The sediment pre-filter and carbon stages last six to twelve months depending on your water quality and how much drinking water you draw from the RO faucet. The membrane itself lasts two to three years under normal conditions. Phoenix water's high TDS and chloramine load can shorten those intervals. If the flow rate from the faucet drops or the water starts tasting different, the filters are due even if the calendar says otherwise. We offer a maintenance plan that covers the replacements on a schedule.
Traditional systems send three to four gallons down the drain for every gallon of filtered water they produce. Newer high-efficiency units cut that ratio closer to one to one. We carry both types, and we will tell you honestly which efficiency level makes sense for your usage and your water quality. The reject water is clean enough for landscaping use if you want to route the drain line outside instead of to the sink drain.
They solve different problems. A softener uses ion exchange to remove calcium and magnesium from your whole-house supply, which protects pipes, fixtures, and the water heater from scale. An RO system removes dissolved solids, chemicals, and contaminants from drinking water at a single faucet. Running a softener upstream of the RO keeps mineral scale off the membrane, which extends its life, and the RO removes the sodium the softener adds. Our filtration options comparison covers how RO fits alongside other point-of-use and whole-house approaches.
Yes, though they are a different class of project from a point-of-use unit under the sink. A whole-home system requires a larger membrane assembly, a storage tank that holds hundreds of gallons, a booster pump to re-pressurize the treated water, and usually a pre-treatment stage for sediment and hardness. They cost significantly more and consume more water than a drinking-water unit. For most Phoenix households, an under-sink RO at the kitchen faucet paired with a whole-house softener covers the bases without the complexity and waste of a full-house membrane system.
Most people notice the difference immediately. Phoenix tap water carries a persistent chloramine flavor and a mineral quality from the high dissolved solids. RO removes both. The filtered water tastes neutral and clean, closer to what you would get from a bottled brand than from the kitchen tap. If you prefer some mineral content in your drinking water, a remineralization stage can be added after the membrane to put a controlled amount of calcium and magnesium back in.