An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

National Pollutant Discharge Elimination System (NPDES)

Status of Nutrient Requirements for NPDES-Permitted Facilities--Majors with Monitoring Requirements

Table 3. Number and Percent of Major Municipal Sewage Treatment Facilities with Nitrogen (N) and/or Phosphorus (P) Monitoring Requirements for Monitoring Only Purposes or for Compliance with an Effluent Limit

This table represents the total number of individual permitted WWTFs that have monitoring requirements for nitrogen only, phosphorus only, or have monitoring requirements for both pollutants. These data include all individual, non-stormwater NPDES permitted facilities with data in ICIS as of February 2016. (These data include EPA-issued permits and tribal permits. These data only include requirements with measuring units that are either mass-based or concentration-based. WWTFs are publicly-owned treatment works (POTWs) with the primary permit standard industrial classification ("SIC") code 4952, and where there is no SIC code, the Facility Type Indicator field is labled "POTW.")

EPA Region State  Universe of
Majors
Nitrogen Only
(Number)
Nitrogen Only
(Percent)
Phosphorus Only
(Number)
Phosphorus Only
(Percent)
Both
N and P
(Number)
Both
N and P
(Percent)
Any
(N or P or Both)
(Number)
Any
(N or P or Both)
(Percent)
10 AK 20 1 5 0 0 0 0 1 5
4 AL 119 0 0 0 0 119 100 119 100
6 AR 78 6 8 9 12 51 65 66 85
9 AS(4) 2 0 0 0 0 0 0 0 0
9 AZ 48 0 0 0 0 43 90 43 90
9 CA 175 26 15 2 1 116 66 144 82
8 CO 91 26 29 3 3 5 5 34 37
1 CT(2) 64 0 0 42 66 2 3 44 69
3 DC 2 0 0 0 0 2 100 2 100
3 DE 8 1 13 0 0 4 50 5 63
4 FL(5) 94 3 3 8 9 35 37 46 49
4 GA 151 0 0 78 52 43 28 121 80
6 GM(4) 0 0 0 0 0 0 0 0 0
9 GU(4) 3 0 0 0 0 0 0 0 0
9 HI 2 0 0 0 0 2 100 2 100
7 IA(3),(6) 96 2 2 5 5 51 53 58 60
10 ID 28 1 4 3 11 22 79 26 93
5 IL 214 27 13 20 9 149 70 196 92
5 IN 133 1 1 75 56 13 10 89 67
7 KS 45 0 0 0 0 45 100 45 100
4 KY 87 10 11 10 11 66 76 86 99
6 LA 105 0 0 1 1 12 11 13 12
1 MA 91 21 23 18 20 43 47 82 90
3 MD 47 0 0 0 0 47 100 47 100
1 ME 61 0 0 14 23 0 0 14 23
5 MI 105 0 0 20 19 0 0 20 19
5 MN 75 15 20 9 12 50 67 74 99
7 MO 123 3 2 1 1 30 24 34 28
9 MP(4) 2 0 0 0 0 0 0 0 0
4 MS 65 0 0 0 0 61 94 61 94
8 MT 21 1 5 0 0 20 95 21 100
4 NC(2) 147 24 16 0 0 106 72 130 88
8 ND(3) 16 0 0 0 0 8 50 8 50
7 NE 30 0 0 0 0 24 80 24 80
1 NH 36 6 17 15 42 2 6 23 64
2 NJ(3),(7) 92 2 2 17 18 44 48 63 68
6 NM 22 1 5 1 5 1 5 3 14
9 NV 7 1 14 0 0 6 86 7 100
2 NY 211 83 39 8 4 90 43 181 86
5 OH 205 79 39 1 0 120 59 200 98
6 OK 69 2 3 0 0 1 1 3 4
10 OR 50 2 4 0 0 26 52 28 56
3 PA 291 12 4 8 3 196 67 216 74
2 PR(4) 33 5 15 0 0 0 0 5 15
1 RI 19 10 53 0 0 9 47 19 100
4 SC 98 18 18 3 3 56 57 77 79
8 SD 20 6 30 0 0 5 25 11 55
4 TN 107 2 2 0 0 83 78 85 79
6 TX(8) 489 7 1 9 2 6 1 22 4
8 UT 29 0 0 1 3 23 79 24 83
3 VA(2) 92 12 13 3 3 22 24 37 40
2 VI(4) 2 0 0 2 100 0 0 2 100
1 VT(3) 0 0 0 0 0 0 0 0 0
10 WA(3) 48 2 4 1 2 35 73 38 79
5 WI 86 0 0 69 80 17 20 86 100
3 WV 50 0 0 0 0 18 36 18 36
8 WY(3) 16 1 6 1 6 0 0 2 13
Total   4,420 419 9 457 10 1,929 44 2,805 63

Notes:
(1) Note that all permits with limits should also have corresponding monitoring requirements for each parameter that is limited to track compliance.
(2) These states have watershed-based permitting for multiple dischargers for nutrients. These permits/facilities may not be reflected in this table. (VA - approximately 112 WWTFs covered for N & P; NC - approximately 54 WWTF covered for N; and CT - approximately 79 facilities covered for N)
(3) IA, ND, VT, WA, and WY did not have primary SIC codes entered into the Permit Basic Info section of ICIS for most or all of their facilities. NJ has only entered SIC codes for 46 percent of its individual permittees in ICIS.
(4) The following territories and regions are included in these tables: American Samoa (AS), Gulf of Mexico (GM), Guam (GU), Northern Mariana Islands (MP), Puerto Rico (PR), and U.S. Virgin Islands (VI).
(5) Upon review, this state indicated that it uses other monitoring location codes in addition to the ones used for this analysis. [FL]
(6) Iowa is in the process of transitioning to a new NPDES database and is working to ensuring accurate transfer and migration of required data into the EPA ICIS-NPDES data system. This process is expected to be complete by summer 2017.
(7) This state noted that its data are batch-loaded into ICIS, and therefore there are some errors based on the state's records. [NJ]
(8) This state indicated that the data managed to capture 12 permits that are either for stormwater (MS4) or industrial facilities. [TX]

Top of Page