A whole-house water filter treats the water where it enters your home, so every tap and shower gets filtered water. In San Antonio it can be paired with a softener, because the two do different jobs. This page explains what a whole-house filter can and cannot do on SAWS water, the standards to ask about, and how to keep one working.
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What a whole-house filter is for
Start with the question the Texas Commission on Environmental Quality puts first: “What contaminant do you want to remove or reduce?” A whole-house filter is the answer when the thing you want to change is in the water at every tap. Reasons include a chlorine taste or smell, sediment, or a specific contaminant you have found in a test. The filter’s certification tells you what it has been shown to reduce.
| Standard | What it covers |
|---|---|
| NSF/ANSI 42 | Aesthetic effects such as chlorine, taste and odor |
| NSF/ANSI 53 | Health effects such as lead |
| NSF/ANSI 401 | Incidental contaminants |
TCEQ’s advice is to select a unit certified by NSF, Underwriter’s Laboratory or the Water Quality Association to remove the contaminant you are concerned about, and to make sure it is certified for that contaminant. Ask any installer which standard their filter is certified to, and for which contaminants.
What a filter does not do: hardness
A whole-house filter is not a softener. SAWS gives a typical hardness of 15 to 20 grains per gallon, and removing that hardness is the job of a softener certified to NSF/ANSI 44. If your complaint is white crust, spots on glasses and soap scum, a filter alone will not fix it. If your complaints are scale and a chlorine taste, you are looking at two pieces of equipment. The water softener page covers that side.
Filter and softener together
Where a house has both, the installer decides the order on the main line and explains why. Ask how the filter and softener will be arranged in your house, whether a sediment prefilter is part of the plan, and how each piece can be bypassed for service without shutting off water to the house.
Want filtered water at every tap? Ask an independent San Antonio pro for a quote.
Request a quoteDrinking water: whole house or one tap
If what you really want is better drinking and cooking water, a filter or a reverse osmosis unit at the kitchen sink may do it without treating the whole house. The standard for RO units is NSF/ANSI 58, and RO is covered on the reverse osmosis page. A whole-house filter makes most sense when the problem is in the shower and the laundry as well as the glass.
Sediment filters
Not every whole-house filter is about taste. A sediment filter catches sand, grit and particles, and it can sit ahead of other equipment to protect it. If you see grit in faucet aerators or a cloudy layer that settles in a glass, say so when you ask for a quote, and ask whether a sediment stage is part of the plan.
Comparing two filter quotes
Whole-house filter quotes can look alike and differ underneath. Put them side by side and check that both name the same things in writing: the filter model and its NSF/ANSI certification and contaminants, the cartridge and its maker’s change schedule, where it goes on the main line and whether a bypass is included, the Texas license held by the installer and the permit that applies. A quote that leaves out the cartridge schedule leaves out part of what the filter costs to own.
Keeping a whole-house filter working
A filter’s cartridge or media has a limited capacity. Change it on the schedule its maker gives for your model and your water, not on a guess. Ask the installer to show you how to change the cartridge or to quote for doing it, and to note the cartridge part number so you can buy the right one.
License and permit
In Texas, anyone who under contract installs, connects or services water treatment equipment needs a TCEQ Water Treatment Specialist license unless exempt, and plumbers licensed under Texas Occupations Code Chapter 1301 are exempt. In the City of San Antonio, Information Bulletin 121c puts the like-for-like replacement of an existing “water purifier/water softener”, and installing one in a building already pre-plumbed for it, under the Limited Service Repair permit; other work needs a regular plumbing permit. Ask the installer which applies to your filter.
Questions to ask
- What will this filter reduce, and which NSF/ANSI standard is it certified to?
- Do I also need a softener for SAWS hardness?
- Where will it go on the main line, and is there a bypass?
- What cartridge does it take, and what is the maker’s change schedule?
- Which Texas license do you hold, and which permit applies?
Questions people ask
Does a whole-house filter soften water?
No. Softening is a softener’s job, under NSF/ANSI 44. A filter deals with taste, odor or specific contaminants.
Do I need a whole-house filter in San Antonio?
Only if there is something at every tap you want to change, such as taste or odor. SAWS says hard water is not a health hazard; read your utility’s annual report and test your water first.
How often do I change the cartridge?
On the maker’s schedule for your model and your water. Ask the installer for the part number and the schedule in writing.
Whole-house filter or a filter at the kitchen sink?
If the problem shows up only in drinking and cooking water, a certified filter or RO unit at the sink may be enough. If it is in the shower and the laundry as well, a whole-house filter treats every tap. A test of your water helps decide.
Who can install a whole-house filter in Texas?
Under TCEQ’s rule, someone who installs water treatment equipment under contract needs a Water Treatment Specialist license unless exempt, and Texas licensed plumbers are exempt.
