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Table 3

Water quality of source and stored household water in Korogocho and Mukuru informal settlements, Nairobi, February 2010

% (n)Geometric mean MPN (95% CI)Median free chlorinea (range)Median total chlorine (range)
SettlementKorogochoMukuruKorogochoMukuruKorogochoMukuruKorogochoMukuru
Source waters 
Total coliform contaminationb (n = 96, 97- Korogocho, Mukuru) 26 (27) 32 (33) 1.3 (0.9–2.0) 1.7 (1.1–2.7) 0.6 (0.0–0.9) 0.4 (0.0–0.8) 0.7 (0.1–1.2) 0.5 (0.0–1.0) 
 Public tap/standpipe (n = 92, 75) 23 (25) 19 (25) 1.2 (0.8–1.7) 1.7 (0.9–3.0) 0.6 (0.1–0.9) 0.4 (0.0–0.8) 0.7 (0.3–1.2) 0.6 (0.0–1.0) 
 Storage tank (n = 3, 1) 2 (67) 13.4 0.5 0.1 (0.0–0.9) 0.4 0.2 (0.1–1.0) 0.5 
 Water tanker (n = 1, 14) 1 (100) 8 (57) 90.9 1.5 (0.7–3.2) 0.5 0.3 (0.0–0.7) 0.7 0.5 (0.0–0.8) 
 Borehole (n = 0, 6) – 4 (57) – 2.9 (0.2–51.4) – 0.0 (0.0–0.1) – 0.0 (0.0–0.1) 
 Water vendor (n = 0, 1) – 1 (100) – 3.1 – 0.5 – 0.7 
E. coli contaminationb (n = 96, 98) 7 (7) 8 (8) 0.6 (0.5–0.7) 0.7 (0.5–0.9) 0.6 (0.0–0.9) 0.4 (0.0–0.8) 0.7 (0.1–1.2) 0.5 (0.0–1.0) 
 Public tap/standpipe (n = 92, 75) 5 (5) 7 (9) 0.6 (0.5–0.7) 0.7 (0.5–0.9) 0.6 (0.1–0.9) 0.4 (0.0–0.8) 0.7 (0.3–1.2) 0.6 (0.0–1.0) 
 Storage tank (n = 3, 1) 1 (33) 1.6 (0.0–257.3) 0.5 0.1 (0.0–0.9) 0.4 0.2 (0.1–1.0) 0.5 
 Water tanker (n = 1, 14) 1 (100) 0.5 0.5 0.3 (0.0–0.7) 0.7 0.5 (0.0–0.8) 
 Borehole (n = 0, 7) – 1 (14) – 1.1 (0.2–7.4) – 0.0 (0.0–0.1) – 0.0 (0.0–0.1) 
 Water vendor (n = 0, 1) – – – – 0.5 – 0.7 
Household waters 
Total coliform contamination (n = 96, 97) 56 (58) 66 (67) 6.4 (3.4–11.8) 21.9 (11.0–43.5) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 Narrow-mouthed container (n = 61, 67) 31 (51) 46 (69) 5.1 (2.3–11.2) 19.3 (8.6–43.2) 0.3 (0.0–0.8) 0.1 (0–1.5) 0.4 (0.0–0.9) 0.2 (0.0–2.0) 
 Covered container (n = 69, 78) 42 (61) 54 (68) 7.1 (3.4–15.0) 23.0 (10.8–49.0) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 20-L jerry can (n = 36, 51) 20 (56) 36 (71) 4.2 (1.6–10.8) 12.6 (5.3–30.0) 0.4 (0.0–0.8) 0.1 (0–1.6) 0.5 (0.0–0.9) 0.2 (0.0–1.7) 
 5-L jerry can (n = 12, 13) 10 (83) 8 (62) 32.8 (3.7–289.8) 38.6 (3.8–390.6) 0.3 (0.0–0.7) 0.1 (0–0.9) 0.4 (0.0–0.9) 0.2 (0.0–1.1) 
 Super drum (50–200 L) (n = 18, 11) 11 (61) 6 (55) 7.1 (1.7–30.0) 40.7 (2.3–718.8) 0.1 (0.0–1.5) 0.0 (0.0–1.5) 0.3 (0.0–1.8) 0.1 (0.0–2.5) 
E. coli contamination (n = 96, 97) 11 (11) 31 (32) 0.7 (0.5–0.8) 1.3 (0.9–1.8) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 Narrow-mouthed container (n = 61, 67) 5 (8) 19 (28) 0.6 (0.5–0.8) 1.3 (0.8–2.2) 0.3 (0.0–0.8) 0.1 (0–1.5) 0.4 (0.0–0.9) 0.2 (0.0–2.0) 
 Covered container (n = 69, 78) 9 (13) 25 (32) 0.7 (0.5–1.0) 1.2 (0.8–1.7) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 20-L jerry can (n = 36, 51) 4 (11) 13 (25) 0.8 (0.5–1.4) 0.9 (0.7–1.3) 0.4 (0.0–0.8) 0.1 (0–1.6) 0.5 (0.0–0.9) 0.2 (0.0–1.7) 
 5-L jerry can (n = 12, 13) 1 (8) 3 (23) 0.5 (0.5–0.6) 1.7 (0.4–7.4) 0.3 (0.0–0.7) 0.1 (0–0.9) 0.4 (0.0–0.9) 0.2 (0.0–1.1) 
 Super drum (50–200L) (n = 18, 11) 5 (28) 5 (45) 0.9 (0.5–1.6) 2.8 (0.5–15.8) 0.1 (0.0–1.5) 0.0 (0.0–1.5) 0.3 (0.0–1.8) 0.1 (0.0–2.5) 
% (n)Geometric mean MPN (95% CI)Median free chlorinea (range)Median total chlorine (range)
SettlementKorogochoMukuruKorogochoMukuruKorogochoMukuruKorogochoMukuru
Source waters 
Total coliform contaminationb (n = 96, 97- Korogocho, Mukuru) 26 (27) 32 (33) 1.3 (0.9–2.0) 1.7 (1.1–2.7) 0.6 (0.0–0.9) 0.4 (0.0–0.8) 0.7 (0.1–1.2) 0.5 (0.0–1.0) 
 Public tap/standpipe (n = 92, 75) 23 (25) 19 (25) 1.2 (0.8–1.7) 1.7 (0.9–3.0) 0.6 (0.1–0.9) 0.4 (0.0–0.8) 0.7 (0.3–1.2) 0.6 (0.0–1.0) 
 Storage tank (n = 3, 1) 2 (67) 13.4 0.5 0.1 (0.0–0.9) 0.4 0.2 (0.1–1.0) 0.5 
 Water tanker (n = 1, 14) 1 (100) 8 (57) 90.9 1.5 (0.7–3.2) 0.5 0.3 (0.0–0.7) 0.7 0.5 (0.0–0.8) 
 Borehole (n = 0, 6) – 4 (57) – 2.9 (0.2–51.4) – 0.0 (0.0–0.1) – 0.0 (0.0–0.1) 
 Water vendor (n = 0, 1) – 1 (100) – 3.1 – 0.5 – 0.7 
E. coli contaminationb (n = 96, 98) 7 (7) 8 (8) 0.6 (0.5–0.7) 0.7 (0.5–0.9) 0.6 (0.0–0.9) 0.4 (0.0–0.8) 0.7 (0.1–1.2) 0.5 (0.0–1.0) 
 Public tap/standpipe (n = 92, 75) 5 (5) 7 (9) 0.6 (0.5–0.7) 0.7 (0.5–0.9) 0.6 (0.1–0.9) 0.4 (0.0–0.8) 0.7 (0.3–1.2) 0.6 (0.0–1.0) 
 Storage tank (n = 3, 1) 1 (33) 1.6 (0.0–257.3) 0.5 0.1 (0.0–0.9) 0.4 0.2 (0.1–1.0) 0.5 
 Water tanker (n = 1, 14) 1 (100) 0.5 0.5 0.3 (0.0–0.7) 0.7 0.5 (0.0–0.8) 
 Borehole (n = 0, 7) – 1 (14) – 1.1 (0.2–7.4) – 0.0 (0.0–0.1) – 0.0 (0.0–0.1) 
 Water vendor (n = 0, 1) – – – – 0.5 – 0.7 
Household waters 
Total coliform contamination (n = 96, 97) 56 (58) 66 (67) 6.4 (3.4–11.8) 21.9 (11.0–43.5) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 Narrow-mouthed container (n = 61, 67) 31 (51) 46 (69) 5.1 (2.3–11.2) 19.3 (8.6–43.2) 0.3 (0.0–0.8) 0.1 (0–1.5) 0.4 (0.0–0.9) 0.2 (0.0–2.0) 
 Covered container (n = 69, 78) 42 (61) 54 (68) 7.1 (3.4–15.0) 23.0 (10.8–49.0) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 20-L jerry can (n = 36, 51) 20 (56) 36 (71) 4.2 (1.6–10.8) 12.6 (5.3–30.0) 0.4 (0.0–0.8) 0.1 (0–1.6) 0.5 (0.0–0.9) 0.2 (0.0–1.7) 
 5-L jerry can (n = 12, 13) 10 (83) 8 (62) 32.8 (3.7–289.8) 38.6 (3.8–390.6) 0.3 (0.0–0.7) 0.1 (0–0.9) 0.4 (0.0–0.9) 0.2 (0.0–1.1) 
 Super drum (50–200 L) (n = 18, 11) 11 (61) 6 (55) 7.1 (1.7–30.0) 40.7 (2.3–718.8) 0.1 (0.0–1.5) 0.0 (0.0–1.5) 0.3 (0.0–1.8) 0.1 (0.0–2.5) 
E. coli contamination (n = 96, 97) 11 (11) 31 (32) 0.7 (0.5–0.8) 1.3 (0.9–1.8) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 Narrow-mouthed container (n = 61, 67) 5 (8) 19 (28) 0.6 (0.5–0.8) 1.3 (0.8–2.2) 0.3 (0.0–0.8) 0.1 (0–1.5) 0.4 (0.0–0.9) 0.2 (0.0–2.0) 
 Covered container (n = 69, 78) 9 (13) 25 (32) 0.7 (0.5–1.0) 1.2 (0.8–1.7) 0.3 (0.0–1.5) 0.0 (0–1.6) 0.4 (0.0–1.8) 0.1 (0.0–2.5) 
 20-L jerry can (n = 36, 51) 4 (11) 13 (25) 0.8 (0.5–1.4) 0.9 (0.7–1.3) 0.4 (0.0–0.8) 0.1 (0–1.6) 0.5 (0.0–0.9) 0.2 (0.0–1.7) 
 5-L jerry can (n = 12, 13) 1 (8) 3 (23) 0.5 (0.5–0.6) 1.7 (0.4–7.4) 0.3 (0.0–0.7) 0.1 (0–0.9) 0.4 (0.0–0.9) 0.2 (0.0–1.1) 
 Super drum (50–200L) (n = 18, 11) 5 (28) 5 (45) 0.9 (0.5–1.6) 2.8 (0.5–15.8) 0.1 (0.0–1.5) 0.0 (0.0–1.5) 0.3 (0.0–1.8) 0.1 (0.0–2.5) 

aThe recommendations for FCR in drinking water in centralized systems and HWTS during a cholera outbreak are 1.0 mg/L and 0.2 mg/L–2.0 mg/L, respectively.

bContamination was defined as any value greater than ≥1 cfu/100 mL. Percentages are based on all samples and not just those with contamination.

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