Pool care articles
How often should I test my pool in Austin?
Test chlorine and pH at least twice a day, and more often when the pool is busy: that is the CDC's advice for home pools and hot tubs. Sunlight, swimmers and, in a hot tub, the jets can all lower chlorine between checks. Sullivan's Pool Service tests and balances backyard pools across Austin on its weekly visits.
If you own a pool in Austin or a nearby community, the CDC's guidance starts with how often to test: chlorine and pH should be checked at least twice each day, with extra checks whenever the pool sees heavy use.
Sullivan's Pool Service is a local company that looks after backyard pools in Austin and nearby communities such as Bee Cave on regular weekly visits. Water testing and balancing is part of that work, but even a well-maintained pool between visits depends on the owner noticing what the water is doing. This note walks through the CDC's recommendations as they apply to a single backyard pool or spa.
Why sun and swimmers drain your chlorine
Among the things the CDC lists that can lower chlorine are sunlight, whatever swimmers carry into the water and, in a hot tub, the jets. That is the reason behind checking twice a day and adding checks when the pool is busy.
The CDC treats chlorine and pH as the first line of defense against germs in residential pools and hot tubs, which is why it asks owners to test and adjust both routinely. In other words, the reading is the tool, not a guess based on how the water looks or smells.
Different numbers for a pool and a spa
The guidance does not give one chlorine target for everything. For a home pool, it recommends free chlorine of at least 1 ppm. A hot tub calls for at least 3 ppm. Both share a pH range of 7.0 to 7.8. A separate CDC swimming-safety page describes a typical residential range of 1 to 4 ppm chlorine, or 3 to 8 ppm bromine.
That split matters when you own both a pool and a spa. A reading that passes in one does not automatically pass in the other, so it helps to know which vessel you tested.
If you use stabilized chlorine
Pools treated with cyanuric acid, or with stabilized products such as dichlor or trichlor, carry an added condition: the CDC recommends at least 2 ppm free chlorine for those pools. It also notes that disinfection takes longer when cyanuric acid is present. The recommendation against cyanuric acid and stabilized chlorine products applies to hot tubs, so a spa owner should not carry pool habits across.
pH gets its own watch
The CDC asks for pH between 7.0 and 7.8. Higher pH makes chlorine less effective, especially above 8.0, while pH below 7.0 raises the chance that pool or hot tub pipes corrode or break down. Water outside that range can also irritate skin and eyes and wear on equipment, which is why pH belongs in every test alongside the chlorine number.
What a test kit can and cannot show
For measuring chlorine and pH, the CDC points to a DPD test kit as the most accurate choice. Strips are acceptable but less precise. One caution applies when a pool is heavily chlorinated: a sample above 10 ppm can bleach the reagent partly or completely, yielding a falsely low reading or a zero. So an oddly low result in a freshly shocked pool may be the test failing, not the water.
The people half of pool safety
The CDC's advice reaches past the water itself. Anyone with diarrhea should stay out, swimmers should not swallow pool water or urinate or defecate in it, and everyone should shower for at least 1 minute before getting in. Children need a bathroom break or diaper check every hour, with changes done away from the pool edge. On the chemical side, follow the label, use appropriate protective equipment, and keep products secure and away from children and pets. Broader safety steps include constant supervision, basic swimming skills, Coast Guard-approved life jackets used as directed, four-sided fencing with self-closing, self-latching gates, and door or window locks and alarms.
What comes out of your hose in Austin
One more local factor: the water you top up with has its own chemistry. Austin Water treats drinking water at three plants, Davis, Ullrich and Handcox, and publishes quarterly summaries of what leaves each one. In the Austin Water quarterly table, the finished water at each plant's tap had a pH of 9.70 at Davis, 9.74 at Ullrich and 9.65 at Handcox. Total hardness was 76 mg/L as CaCO3 at Davis and 77 mg/L at both Ullrich and Handcox. Total alkalinity as CaCO3 read 52 mg/L at the Davis tap, 51 mg/L at Ullrich and 60 mg/L at Handcox. Total chloramines measured 2.69 mg/L at Davis, 2.52 mg/L at Ullrich and 2.60 mg/L at Handcox.
Those are quarterly averages for the water leaving the plants, not readings of your pool, so after a top-up the CDC's routine-testing advice still applies: measure the pool itself rather than assuming anything about it.
Sources
In Austin
Fill water matters here. Austin Water reported finished water leaving its three plants in the second quarter of 2026 at pH 9.65 to 9.74, total hardness of 76 to 77 mg/L as CaCO3, total alkalinity of 51 to 60 mg/L, and 2.52 to 2.69 mg/L of chloramines. Those are averages for tap water, not readings of your pool, so test the pool itself after a top-up.
Related articles
- Why does my pool smell strongly of chlorine?
- What is combined chlorine and how to measure it
- How fast does chlorine kill pool germs?
Sullivan’s Pool Service maintains pools in and around Austin, including Northwest Hills, South Austin, West Lake Hills, Tarrytown, Great Hills, River Place, Crestview, East Austin, North Austin, West Campus, Hyde Park, Downtown Austin and St. Johns, and in Bee Cave, Cedar Park, Georgetown, Leander, Pflugerville and Round Rock. See every service area.
Weekly residential service has one fixed monthly price, set by pool size: see pool service pricing for what each size tier covers.
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