GroundRules
9VAC25-790-960: Influent and effluent sampling
Where this section sits in the code
- Title 9. Environment
- Agency 25. State Water Control Board
- Chapter 790. Sewage Collection and Treatment Regulations
- Part IV. Reports and Forms
- Article 1. Reports
A. Sampling tests and frequency. Table C lists the typical recommended minimum sampling program schedules for all sewage treatment works (STW).
B. STW effluent tests and frequency of effluent testing and frequency of other sampling for a treatment works will be provided in the VPDES permit or the VPA permit.
TABLE C. TYPICAL SAMPLING PROGRAMS FOR SEWAGE TREATMENT WORKS.
PLANT SIZE
>2.01 MGD
1.0-2.0 MGD
0.101-0.999 MGD
0.401-0.1 MGD
0.0011-0.04 MGD
Flow
Totalizing, Indicating & Recording
Totalizing, Indicating & Recording
Totalizing, Indicating & Recording
Totalizing, Indicating & Recording
Estimate
BOD5, TSS, TKN
24- HC
1/ Day
24- HC
5 Days/ Wk
8-HC
3 Days/ Wk
4-HC
1 Day/ Wk
Grab
1/month
Total Nitrogen* Total Phosphorus*
24- HC
1/ Week
24- HC
1/ Week
8-HC
1/ 2 Weeks
4-HC
1/ Month
Grab
1/month
TRC, Contact tank**
Grab 1/2 Hr
4/Day at 4 Hr.Intervals
3/Day at 4 Hr.Intervals
3/Day at 4 Hr.Intervals
Grab
1/Day
Fecal Coliform**
Grab
1/Day
10am-4pm
Grab
5 Days/Wk
10am-4pm
Grab
3 Days/Wk
10am-4pm
Grab
1/Week
10am-4pm
Grab
1/Month
10am-4pm
pH, DO, TRC Effluent
Grab
1/Day
Grab
1/Day
Grab
1/Day
Grab
1/Day
Grab
1/Day
WQS Parameters (Toxics)
1/8,24 HC or 1/month
1/8,24 HC or 1/month
1/8, 8HC or 1/month
1/8, 4HC or 1/month
Grab
1/month
Collected 2026-09-14T04:49:25Z. Source file · JSON