Public-Aquatics Fecal Incident Response
Close, classify, disinfect, document, and reopen a public aquatic venue after formed stool, diarrhea, or an uncertain fecal incident.
Field checklist
A concise reminder for a trained technician. Use the full procedure for first-time work or unusual conditions.
Complete in order
- Close every venue on the affected circulation system and record the event time.
- Classify the stool as formed, diarrheal, or uncertain; use the more protective path when unsure.
- Remove material with a net or bucket, never a vacuum, and control tools, PPE, and waste.
- Measure chlorine, pH, temperature, CYA, circulation, and volume before selecting the approved treatment path.
- Maintain and record every required condition, complete filter or drain actions, then verify the reopening range.
Done when
- The adopted response is complete, treatment conditions are documented, waste is controlled, and authorized reopening criteria are met.
Close first. Classify second. Treat only after you know which water is connected, which rule controls, and whether the stool was formed or diarrheal.
This procedure covers feces in a public or commercially operated aquatic venue. Use Fecal, Vomit, Blood, Dead Animal, Sharps, and Other Contamination for immediate exposure care and non-fecal contamination.
Why this matters
Diarrhea can release Cryptosporidium, a parasite that can remain infectious for days in normally chlorinated water. Formed stool usually releases less material, but it can still carry pathogens and protect them from disinfectant until removed.
The two events do not share one treatment. Cyanuric acid also slows chlorine inactivation and materially changes the diarrheal response. Guessing can produce a closure that is too short, a chlorine level the test kit cannot measure, or an exposure that damages equipment and hurts staff.
Before you begin
Use the facility's adopted response plan and current state or local requirement. The CDC values on this page are a national public-health recommendation, not permission to ignore the rule governing the facility.
Confirm a trained operator is responsible, the exact circulation map and volume are available, and treatment will remain within equipment, surface, ventilation, discharge, and product limits. Prepare independent tests that can measure the intended chlorine range. An ordinary comparator that stops at 5 or 10 ppm cannot verify 20 ppm.
Have closure signs or barriers, a dedicated net or bucket, disposable gloves, required chemical PPE, sanitary waste supplies, a timer, and the incident log ready before disturbing the material.
Detailed procedure
1. Close the connected system
Clear bathers from the affected venue. Close every pool, spa, catch basin, surge tank, feature, or other venue that shares the recirculation system. Stop splash and aerosol features when safe, but keep required treatment circulation available for the approved response.
Record when the event was reported and when closure began. Preserve any useful witness description without collecting unnecessary medical information.
2. Classify the incident
Classify the stool as:
- formed: solid and contained;
- diarrheal: loose, liquid, dispersed, or associated with reported diarrhea;
- uncertain: the appearance or report does not support a confident choice.
Use the diarrheal path for uncertain stool. Do not let convenience turn an ambiguous event into a formed-stool response.
3. Remove material without vacuuming
Put on the required PPE. Remove as much material as possible with a net or bucket. Do not vacuum feces into the recirculation system, filter, portable vacuum, or wastewater container.
Dispose of material sanitarily. Clean the removal tool, then disinfect it as the response plan directs. Remove gloves without contaminating skin or clothing and wash hands thoroughly with soap and water.
4. Establish the treatment conditions
Measure and record:
- free chlorine and pH;
- water temperature;
- CYA, including recent use of stabilized chlorine;
- verified system volume;
- active filtration and circulation;
- connected venues and features;
- filter type, chemical-feed limits, secondary treatment, and discharge path.
Use Testing and Recording Public Aquatic Water Quality for the sampling record. Never infer CYA from the sanitizer brand alone.
5. Select the approved response
The current CDC aquatic-staff recommendations provide these reference conditions at pH 7.5 or lower, ideally at 77°F or warmer:
| Incident | CDC reference response |
|---|---|
| Formed stool | Maintain 2 ppm free chlorine for 25 to 30 minutes. CDC also publishes equivalent concentration-time choices. |
| Diarrhea without CYA | Achieve a CT value of 15,300 using a feasible approved free-chlorine concentration and maintained time. |
| Diarrhea with 1 to 15 ppm CYA | CDC publishes specific high-range chlorine and extended-time options; select one through the adopted plan. |
| Diarrhea with more than 15 ppm CYA | Lower CYA into the CDC response range before hyperchlorination, or use another approved pathway. |
CT = maintained free chlorine in ppm × time in minutes
For an unstabilized diarrheal response, CDC examples include 20 ppm for 765 minutes or 10 ppm for 1,530 minutes. Do not substitute those examples for the full protocol. Temperature, pH, circulation, CYA, test range, equipment limits, and local rules remain controlling conditions.
For CYA from 1 to 15 ppm, use the exact current CDC table and facility procedure. Do not calculate a shorter time by applying the unstabilized CT formula to stabilized water.
6. Dose and maintain the conditions
Use unstabilized chlorine when the selected procedure calls for it. Calculate the addition from verified volume, measured starting residual, product strength, and label directions. Use Calculating and Adding Pool Chemicals and the facility chemical plan.
Keep the venue closed. Confirm filtration and circulation operate throughout the interval. Test often enough to prove the target was maintained, not merely reached once. If chlorine or pH leaves the required condition, follow the adopted rule for correcting and restarting or extending the interval.
Do not ask automation to control outside its approved measurement range. Protect probes, feeders, heaters, covers, finishes, and secondary equipment according to their manuals.
7. Complete filter, media, or drain actions
After a diarrheal response, follow the required filter and wastewater procedure. CDC calls for thorough backwashing after the target is achieved, discharge directly to waste under state or local rules, and media replacement where appropriate. Do not return contaminated backwash through the filter.
For a small-volume spa, splash feature, or similar venue, full drain, accessible-surface cleaning, appropriate filter-media work, and refill from an approved source may be the safer approved path. Include associated piping, tanks, and features rather than draining only the visible basin.
8. Verify reopening
Reopen only after:
- the complete treatment or drain-clean-refill path is documented;
- free chlorine and pH are within the jurisdiction's operating range;
- water is clear enough for required bottom and suction-cover visibility;
- circulation, filtration, feed, and safety systems are normal;
- waste and contaminated tools are controlled;
- no unresolved chemical or exposure hazard remains;
- the person authorized by the facility plan approves reopening.
Record the final independent test and actual reopening time. Do not clear the venue from an estimated chlorine-decay time.
Common problems
No one knows whether the stool was formed. Use the diarrheal path. An uncertain description cannot support the shorter response.
The test kit cannot read the target. Stop. Obtain a valid high-range method and trained operator before treatment.
CYA is above the response range. Follow the approved dilution, drain, or alternate pathway. Do not ignore the slowing effect.
The facility has shared filtration. Close and treat every connected venue. A wall between basins does not separate shared water.
Chlorine fell during the interval. Preserve the readings and use the adopted procedure to determine the renewed treatment time. Do not report an uninterrupted interval.
A patron asks for a reopening time. Explain that reopening depends on maintained treatment, final water conditions, and verification. Do not promise a clock time before the system proves it.
Major stop conditions
Stop the task, leave the system safe, and escalate when any of these conditions apply.
- No trained authorized operator can execute the applicable response or safely measure its required chlorine range.
- The required treatment would exceed equipment, surface, chemical-feed, ventilation, discharge, or occupational-safety limits.
- An illness cluster, suspected outbreak, sewage event, mixed chemical hazard, or regulator-reportable condition requires public-health direction.
For BlueLux technicians, contractors, and partners
What BlueLux does differently
- We map connected water before treating the visible basin as the whole incident.
- We select the response from stool type and measured CYA, not a generic “shock” instruction.
- We record maintained conditions through the full interval and require an independent reopening test.
Document before leaving
- Event time, venue, shared systems, stool classification and basis, closure, notification, and affected operating schedule
- Volume, temperature, starting and maintained free chlorine, pH, CYA, circulation, treatment plan, and actual time interval
- Removal method, tools, PPE, filter or drain action, discharge, waste, final readings, reopening authority, and preventive follow-up
Sources and authority
These are the regulations, official guidance, manufacturer instructions, industry references, and documented operating practices materially used for this entry.
- government guidanceCenters for Disease Control and PreventionSupports closure, formed and diarrheal classification, no-vacuum removal, chlorine-time conditions, CYA adjustment, filtration, waste, reopening, and incident records.Source checked September 10, 2026
- government guidanceCenters for Disease Control and PreventionProvides current CDC context for pathogen risk, immediate removal, public-pool hyperchlorination, small-volume spa response, and aquatic-staff resources.Source checked September 10, 2026
- government guidanceCenters for Disease Control and PreventionSupports written contamination response plans, trained staff, response supplies, records, treatment-system operation, and public-health notification.Source checked September 10, 2026
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