Administrative Code

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Virginia Administrative Code
Title 9. Environment
Agency 25. State Water Control Board
Chapter 31. Virginia Pollutant Discharge Elimination System (VPDES) Permit Regulation

9VAC25-31-570. Frequency of monitoring.

A. Biosolids.

1. The frequency of monitoring for the pollutants listed in Tables 1 through 4 of 9VAC25-31-540; the pathogen density requirements in 9VAC25-31-710 A and B 2 through B 4; and the vector attraction reduction requirements in 9VAC25-31-720 B 1 through B 4, B 7 and B 8 shall be the frequency in Table 1 of this section.


Amount of biosolids*

(metric tons per 365-day period)


Greater than zero but less than 290

once per year

Equal to or greater than 290 but less than 1,500

once per quarter (four times a year)

Equal to or greater than 1,500 but less than 15,000

once per 60 days (six times per year)

Equal to or greater than 15,000

once per month (12 times per year)

*Either the amount of bulk biosolids applied to the land or the amount of biosolids prepared for sale or give-away in a bag or other container for application to the land (dry weight basis).

2. After the biosolids has been monitored for two years at the frequency in Table 1 of this section, the department may reduce the frequency of monitoring for pollutant concentrations and for the pathogen density requirements in 9VAC25-31-710 A 5 b and c.

B. Domestic septage. If either the pathogen requirements in 9VAC25-31-710 C 2 or the vector attraction reduction requirements in 9VAC25-31-720 B 12 are met when domestic septage is applied to agricultural land, forest, or a reclamation site, each container of domestic septage applied to the land shall be monitored for compliance with those requirements.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia; § 402 of the federal Clean Water Act; 40 CFR Parts 122, 123, 124, 403, and 503.

Historical Notes

Derived from Virginia Register Volume 12, Issue 20, eff. July 24, 1996; amended, Virginia Register Volume 16, Issue 25, eff. September 27, 2000; Volume 29, Issue 24, eff. September 1, 2013; Volume 39, Issue 4, eff. November 9, 2022.

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