Table 3. Living environment standard for river in water quality and aquatic ecosystem

Grading		Condition (Character)	Standard
			pH	BOD (mg/L)	COD (mg/L)	TOC (mg/L)	SS (mg/L)	DO (mg/L)	TP (mg/L)	Coliform group (count/100mL)
										Total coliform	Fecal coliform
Very good	Ia		6.5〜8.5	Less than 1	Less than 2	Less than 2	Less than 25	7.5 or more	Less than 0.02	Less than 50	Less than 10
Good	Ib		6.5〜8.5	Less than 2	Less than 4	Less than 3	Less than 25	5.0 or more	Less than 0.04	Less than 500	Less than 100
Slightly good	II		6.5〜8.5	Less than 3	Less than 5	Less than 4	Less than 25	5.0 or more	Less than 0.1	Less than 1,000	Less than 200
Usually	III		6.5〜8.5	Less than 5	Less than 7	Less than 5	Less than 25	5.0 or more	Less than 0.2	Less than 5,000	Less than 1,000
Poor	IV		6.0〜8.5	Less than 8	Less than 9	Less than 6	Less than 100	2.0 or more	Less than 0.3
Bad	V		6.0〜8.5	Less than 10	Less than 11	Less than 8	There should not be litter	2.0 or more	Less than 0.5
Very bad	VI			Greater than 10	Greater than 11	Greater than 8		Under 2.0	Greater than 0.5