Table 2.

Characteristics of drinking water samples

CharacteristicsTypes of drinking water samples
Ground source waterSurface source waterCistern
HPC (CFU/ml)
 No. of samples16896
 Mean ± SE5,700 ± 2,4266,000 ± 2,09139,000 ± 22,700
 Median (range)65.0 (5–30,000)90.0 (1–120,000)7,100 (1–120,000)
Free chlorine (mg/liter)
 Mean ± SE0.40 ± 0.100.61 ± 0.06NCa
 Median (range)0.20 (<0.1–1.0)0.40 (<0.1–2.5)
Total chlorine (mg/liter)
 Mean ± SE0.53 ± 0.100.90 ± 0.10NC
 Median (range)0.50 (<0.1–1.0)0.70 (<0.1–2.8)
Age of sample siteb (yrs)
 No. of sites7433
 Mean ± SE42.0 ± 15.548.0 ± 4.3 25.3 ± 1.2 
 Median (range)20.0 (10–120)40.0 (2–125)26.0 (22–28)
Cold temp (°C)c
 No. of sites7503
 Mean ± SE20.3 ± 0.5 19.0 ± 0.8 22.3 ± 0.8 
 Median (range)20.0 (18.8–25.0)20.0 (10.8–27.0)23.0 (20–24)
Warm temp (°C)d
 No. of sites4303
 Mean ± SE36.7 ± 1.6 41.4 ± 1.1 46.7 ± 3.3 
 Median (range)36.0 (34.0–41.0)40.0 (30.6–59.6)48.0 (38.0–54.0)
  • a NC, not chlorinated.

  • b Age of building or residence where samples were collected.

  • c Temperature of cold tap water.

  • d Temperature of warm tap water or shower sample.