Table 3.

Rainwater pH before and after treatment.

City/regency area	Subdistrict/village	pH before treatment	pH after treatment	Drinking water requirement
Pontianak	Siantan Hulu	4.626	7.001	6.5–8.5
	Siantan Tengah	4.937	6.981
Kubu Raya	Desa Limbung	5.357	6.791
	Desa Kuala Dua	5.721	7.014
Mean		5.16	6.95
Median (min.-max.)		5.06 (4.61–6.09)	6.96 (6.31–7.43)
Sd		0.52	0.21
P a	≤0.001 ∗

Source: primary data; ^aT-test (α = 5%); ^∗significant at p ≤ 0.05.