Test water on a fixed schedule so that problems are caught between emergencies: look at the source and tanks daily, measure turbidity with the tube weekly at the source and the distribution points, and run the hydrogen sulfide bacteria test monthly at the source, the tank outlet and 2-3 distribution points. Add an extra test within 24 hours of any change in treatment, and test at once after heavy rain, repair work, a dead animal near the source or an outbreak of diarrhoea.
Part of Community Water Testing
A monitoring schedule is the plan for what is tested, where in the system, and how often, fixed in advance so that testing happens whether or not anything seems wrong.
Testing Only When There Is A Problem Misses The Slow Decline
The community water testing page lists testing only when there is a problem as a mistake that misses gradual deterioration, and testing only at the source as one that misses contamination in tanks or pipes. A schedule fixes both: it says when, and it says where.
| Interval | What | Where |
|---|---|---|
| Daily | Visual check: colour, smell, turbidity by eye | Source and tanks |
| Weekly | Turbidity tube measurement | Source and distribution points |
| Monthly | H2S bacteria test | Source, tank outlet and 2-3 distribution points |
| Within 24 hours of a change | Test after changing the chlorine dose, switching filters, and so on | Tank outlet and a far tap |
| At once after an event | Rain or flooding, illness, repair, dead animal, visible change, earthquake or landslide | See Event-Triggered Testing |
Where the system chlorinates, a daily chlorine residual reading belongs in the round (System Monitoring). That daily frequency is my suggestion, not part of the page’s list.
What You Need
- A map of the system with each sampling point named
- A written calendar showing who tests what and when
- A kit for each test and enough vials (H2S Test Kit)
- A log (Test Log)
Method: Choose The Points, Then The Dates
Step 1: Pick fixed points that tell different things: the source (what comes in), the tank outlet (what leaves treatment and storage), and distribution points (what the user gets).
Step 2: Choose the distribution points to catch trouble. Always include the farthest tap from the tank, where the chlorine residual is lowest and stagnation is worst. Add a dead-end branch or a low-use tap if there is one, and rotate the others.
Step 3: Fix the dates on the calendar: the same weekday for the tube, the same day each month for the bacteria test.
Step 4: Assign names to each task, with a deputy.
Step 5: Adjust the plan after a failure. A failed test calls for a denser schedule for a while.
Worked Example: A System With One Spring, One Tank, Five Standpipes
Points: the spring, the tank outlet, and three distribution points chosen from the five standpipes, always including the farthest.
- Daily rounds: 365 a year.
- Weekly tube readings at the source and three distribution points: 4 × 52 = 208 a year (add the tank outlet for 5 × 52 = 260).
- Monthly bacteria tests at 5 points: 5 × 12 = 60 vials a year, plus a blank and a positive control each month, 2 × 12 = 24, for 84 in all.
- Rotation: if the farthest standpipe (number 5) is always tested, the other two distribution samples rotate through standpipes 1 to 4. Over two months each is sampled once (1 and 2, then 3 and 4), so every standpipe is covered at least every other month.
An extra test is added after every event on the list, so the calendar number is a floor and not a total.
Common Mistakes
- Testing the same easy tap every time. The weakest point goes unwatched.
- Skipping a month because nothing seemed wrong. The point of the schedule is that it does not depend on that.
- Testing only at the source.
- Not scheduling the deputy. Tests lapse when one person is away.
Safety
A schedule is not a guarantee
A result at the scheduled time speaks for that sample at that moment. Contamination can arise between tests, and a bacteria test can miss low levels or give a clear result the day before an outbreak. Keep the daily look, act on events, and treat the water regardless of recent results.
What’s Next
- Learn next: Routine Testing — doing the scheduled tests well
- Combine with: Event-Triggered Testing — the tests the schedule cannot predict