Pool care articles
Leaves, testing and your pool water
This guide from Sullivan's Pool Service summarizes the cited guidance. Leaves are not the only thing that can lower your pool's chlorine level. Pee, poop, sweat, dirt from swimmers' bodies, sunlight, and hot tub jets that make mist from the water all reduce chlorine, which is why the level must be routinely tested. The CDC recommends testing chlorine and pH at least twice per day, and more often when many people are using the pool or hot tub.
Why debris season changes your testing routine
When leaves start falling into the water, the water itself changes. Organic debris gives chlorine more work to do, and the chlorine level can drop for reasons that are not obvious from the surface. That is why debris season calls for a steady testing habit rather than an occasional glance at the pool.
Chlorine in pool and hot tub water needs to be tested on a routine basis, because plenty of things can lower its concentration. Falling leaves are one example, and they tend to arrive in waves rather than a steady trickle, so the level can shift from one week to the next.
As the owner of a residential pool or hot tub, checking the chlorine concentration and the pH regularly falls to you. Doing so helps protect the people who use the water from swimming-related illnesses. A consistent routine during leaf season keeps small changes from turning into bigger water problems.
What chlorine and pH do for your pool
Chlorine is the sanitizer that keeps pool water safe. It is added to the water to kill germs, though it does not do the job the instant it goes in. Used properly, it can kill most germs within a few minutes, which is why keeping the right level matters so much.
pH plays a supporting role here. When pH stays in the range the CDC recommends for pools, 7.0 to 7.8, chlorine is able to do its work. If the pH drifts out of that range, the chlorine can lose effectiveness even when the level looks fine on a test strip.
The CDC also recommends a chlorine concentration of at least 1 ppm in pools. Hot tubs call for more, at least 3 ppm, because the warmer water and smaller volume change how the sanitizer behaves. Checking both chlorine and pH together gives a fuller picture of the water.
Why pH matters as seasons change
pH is one of those readings that quietly shapes everything else in the water. Keeping it in the 7.0 to 7.8 range does several jobs at once. It helps chlorine do its work against the germs that cause swimming-related illness, it is easier on the pipes in the circulation system, and it feels more comfortable to swimmers, whose eyes and skin notice water that has drifted out of balance.
The connection between pH and chlorine is worth understanding, especially as debris piles up and water chemistry shifts with the seasons. As pH climbs, chlorine loses more and more of its ability to kill germs. Once pH rises past 8.0, that loss becomes especially pronounced, so water can look clean while the sanitizer is quietly underperforming.
If leaves and other organic matter have been dropping into the pool regularly, watching pH becomes even more useful, since it directly affects how well the chlorine in the water can do its job.
What to test and how often
When leaves and other debris start finding their way into the water, testing becomes a daily habit rather than a weekly one. Check the chlorine concentration and the pH at least twice each day. If the pool or spa is getting plenty of use, especially by a group of swimmers, test even more often than that, since heavy use can shift readings quickly between checks.
The tool used for testing matters as much as the schedule. A DPD test kit, which measures chlorine and pH, gives the most accurate results. The name DPD stands for N,N Diethyl-1,4 Phenylenediamine Sulfate, which is the chemical the kit relies on to develop its readings.
Test strips are another option, and many owners keep them on hand for convenience. The tradeoff is accuracy, since strips are less accurate than a DPD kit. For routine checks during debris season, a DPD kit is worth keeping close by.
A quick checklist before your next visit
A short checklist can make the visit go more smoothly. Start by skimming leaves and other debris out of the pool, since anything that falls in can chip away at the water's chlorine. Remember that chlorine and pH work together as the first defense against the germs that can make swimmers sick, so keeping both in range matters.
Before testing, think about what the pool has been through lately. Swimmers bring things on their bodies, such as sweat, dirt, pee, and poop, that use up chlorine. Sunlight does the same, and in a spa, the jets can lift water into droplets or mists that also lower chlorine levels.
Whenever you test, whatever kind of test kit or strips you use, always follow the manufacturer's directions. That simple habit keeps your readings dependable, and dependable readings make every visit more useful.
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 your tech flushes chlorine lines first
- Testing more often after heavy pool use
- Why sunlight lowers your pool chlorine
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.
Tell us about your pool
Tell us your service location and whether you need weekly care, help with equipment, or a one-time service. Call or send the quote form. We’ll confirm availability and the next step for your pool. Repairs and other separately quoted work are discussed before approval.