Guide
Aerobic septic tablets: what to use and never use
Spray-irrigation systems must disinfect effluent before it reaches the lawn. Most Central Texas ATUs use a tablet chlorinator.
Use
- Calcium hypochlorite tablets made and labeled for wastewater (often sold as "septic" or "wastewater" chlorine tablets)
Never use
- Pool or spa tablets (trichlor / trichloroisocyanuric acid). Mixing them with calcium hypochlorite or wastewater can release dangerous gas or cause a fire or explosion. They are not approved for septic chlorinators.
How often
Check the tube monthly. Many households use 1–4 tablets a month, depending on water use. Your maintenance provider checks chlorine residual at each visit. Montgomery County publishes its own tablet chlorination guidance.
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FAQ
Can I use pool chlorine tablets in my aerobic septic system?
No. Pool trichlor tablets are not approved for septic chlorinators and can react dangerously. Use calcium hypochlorite tablets labeled for wastewater.