New York Codes, Rules and Regulations
Title 6 - DEPARTMENT OF ENVIRONMENTAL CONSERVATION
Chapter X - DIVISION OF WATER RESOURCES
Subchapter A - GENERAL
Article 2 - CLASSIFICATIONS AND STANDARDS OF QUALITY AND PURITY
Part 703 - Surface Water and Groundwater Quality Standards and Groundwater Effluent Limitations
Section 703.3 - Water quality standards for pH, dissolved oxygen, dissolved solids, odor, color and turbidity
Standards for specific classes are provided in this section.
| Parameter | Classes | Standard |
| pH | AA, A, B, C, AA-Special, A-Special, GA | Shall not be less than 6.5 nor more than 8.5. |
| D | Shall not be less than 6.0 nor more than 9.5. | |
| SA, SB, SC, I, SD | The normal range shall not be extended by more than one-tenth (0.1) of a pH unit. | |
| Dissolved oxygen (DO) | A-Special | In rivers and upper waters of lakes, not less than 6.0 mg/L at any time. In hypolimnetic waters, it should not be less than necessary for the support of fishlife, particularly cold water species. |
| AA, A, B, C, AA-Special | For trout spawning waters (TS) the DO concentration shall not be less than 7.0 mg/L from other than natural conditions. For trout waters (T), the minimum daily average shall not be less than 6.0 mg/L, and at no time shall the concentration be less than 5.0 mg/L. For nontrout waters, the minimum daily average shall not be less than 5.0 mg/L, and at no time shall the DO concentration be less than 4.0 mg/ L. | |
| D | Shall not be less than 3.0 mg/L at any time. | |
| SA, SB, SC | Chronic: Shall not be less than a daily average of 4.8 mg/L* |
Remark: *The DO concentration may fall below 4.8 mg/L for a limited number of days, as defined by the formula:
DOi = 13.0/2.80 + 1.84e-0.1ti
where DOi = DO
concentration in mg/L between 3.0-4.8 mg/L and ti = time in days. This equation is applied by dividing the DO range of 3.0-4.8 mg/L into a number of equal intervals. DOi is the lower bound of each interval (i) and ti is the allowable number of days that the DO concentration can be within that interval. The actual number of days that the measured DO concentration falls within each interval (i) is divided by the allowable number of days that the DO can fall within interval (ti). The sum of the quotients of all intervals (i...n) cannot exceed 1.0: i.e.,
| n | ti (actual) |
| [SIGMA] | < 1.0 |
| i=1 | ti (allowed) |
The DO concentration shall not fall below the acute standard of 3.0 mg/L at any time.
| SA, SB, SC, SD | Acute: Shall not be less than 3.0 mg/L at any time. | |
| I | Shall not be less than 4.0 mg/L at any time. | |
| Dissolved solids | A-Special | Shall not exceed 200 mg/L. |
| AA, A, B, C, AA-Special, GA | Shall be kept as low as practicable to maintain the best usage of waters but in no case shall it exceed 500 mg/L. | |
| Odor | GA | Shall not exceed a threshold odor number of 3. |
| Color | GA | Shall not exceed 15 color units (platinum-cobalt method). |
| Turbidity | GA | Shall not exceed 5 nephelometric units. |
