CITY OF MOUNT PLEASANT — NPDES permit IA0047970: limits, due date and EPA's record

NPDES permit IA0047970 · Major POTW · effective, expires 2029-06-30 · EPA's file as of 2026-09-19

EPA's record, 2025-09-01 to 2026-08-31

Reporting

Reports are due about 15 days after each monitoring period ends (read off this permit's own late-day counts in EPA's filings).

Limits in force (83)

Outfall	Parameter	Statistic	Limit	Months
002	BOD, 5-day, 20 deg. C	30DA AVG	report only	all year
002	BOD, 5-day, 20 deg. C	DAILY MX	report only	all year
002	BOD, 5-day, 20 deg. C	30DA AVG	report only	all year
002	BOD, 5-day, 20 deg. C	DAILY MX	report only	all year
002	pH	DAILY MN	>= 6 SU	all year
002	pH	DAILY MX	<= 9 SU	all year
002	pH	30DA AVG	report only	all year
002	pH	DAILY MX	report only	all year
002	Solids, total suspended	30DA AVG	<= 30 mg/L	all year
002	Solids, total suspended	7 DA AVG	<= 45 mg/L	all year
002	Solids, total suspended	30DA AVG	<= 1001 lb/d	all year
002	Solids, total suspended	7 DA AVG	<= 1501 lb/d	all year
002	Solids, total suspended	30DA AVG	report only	all year
002	Solids, total suspended	DAILY MX	report only	all year
002	Solids, total suspended	30DA AVG	report only	all year
002	Solids, total suspended	DAILY MX	report only	all year
002	Nitrogen, total [as N]	30DA AVG	report only	all year
002	Nitrogen, total [as N]	DAILY MX	report only	all year
002	Nitrogen, total [as N]	30DA AVG	report only	all year
002	Nitrogen, total [as N]	DAILY MX	report only	all year
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 17.9 mg/L	Nov
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 8.1 mg/L	Jul
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 12.4 mg/L	Oct
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 12 mg/L	Apr
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 18.6 mg/L	Mar
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 13.8 mg/L	May
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 18.6 mg/L	Feb
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 8.5 mg/L	Sep
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 19.3 mg/L	Dec
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 19.2 mg/L	Jan
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 7.7 mg/L	Aug
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 10.5 mg/L	Jun
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 17.9 mg/L	Nov
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 22.1 mg/L	Jul
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 19.2 mg/L	Oct
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 19.1 mg/L	Apr
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 18.6 mg/L	Mar
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 19 mg/L	May
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 18.6 mg/L	Feb
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 20.3 mg/L	Sep
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 19.3 mg/L	Dec
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 19.2 mg/L	Jan
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 20.4 mg/L	Aug
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 18.2 mg/L	Jun
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 598 lb/d	Nov
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 269 lb/d	Jul
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 415 lb/d	Oct
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 401 lb/d	Apr
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 621 lb/d	Mar
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 461 lb/d	May
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 621 lb/d	Feb
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 282 lb/d	Sep
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 645 lb/d	Dec
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 641 lb/d	Jan
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 256 lb/d	Aug
002	Nitrogen, ammonia total [as N]	30DA AVG	<= 350 lb/d	Jun
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 598 lb/d	Nov
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 736 lb/d	Jul
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 642 lb/d	Oct
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 637 lb/d	Apr
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 621 lb/d	Mar
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 633 lb/d	May
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 621 lb/d	Feb
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 677 lb/d	Sep
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 645 lb/d	Dec
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 641 lb/d	Jan
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 682 lb/d	Aug
002	Nitrogen, ammonia total [as N]	DAILY MX	<= 608 lb/d	Jun
002	Nitrogen, Kjeldahl, total [as N]	30DA AVG	report only	all year
002	Nitrogen, Kjeldahl, total [as N]	DAILY MX	report only	all year
002	Nitrogen, Kjeldahl, total [as N]	30DA AVG	report only	all year
002	Nitrogen, Kjeldahl, total [as N]	DAILY MX	report only	all year
002	Phosphorus, total [as P]	30DA AVG	report only	all year
002	Phosphorus, total [as P]	DAILY MX	report only	all year
002	Phosphorus, total [as P]	30DA AVG	report only	all year
002	Phosphorus, total [as P]	DAILY MX	report only	all year
002	E. coli	GEO MEAN	<= 130 #/100mL	Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov
002	Toxicity [acute], Ceriodaphnia dubia	DAILY MX	<= 1 N=0;Y=1	all year
002	Toxicity [acute], Pimephales promelas [Fathead Minnow]	DAILY MX	<= 1 N=0;Y=1	all year
002	BOD, carbonaceous [5 day, 20 C]	30DA AVG	<= 25 mg/L	all year
002	BOD, carbonaceous [5 day, 20 C]	7 DA AVG	<= 40 mg/L	all year
002	BOD, carbonaceous [5 day, 20 C]	30DA AVG	<= 834 lb/d	all year
002	BOD, carbonaceous [5 day, 20 C]	7 DA AVG	<= 1334 lb/d	all year