Cal. Code Regs. tit. 23 § 3937

Current through Register 2024 Notice Reg. No. 43, October 25, 2024

Section 3937 - Revised Bacteria Objectives for Waters Designated for Water Contact Recreation

On October 25, 2001 the Los Angeles Regional Water Quality Control Board (Regional Board), adopted Resolution No. 01-018 amending the Water Quality Control Plan for the Los Angeles Region (Basin Plan). The amendment revised the Basin Plan by incorporating new water quality objectives for bacteria for fresh and marine waters. These objectives update the previous objectives and represent the best data currently available.

On July 8, 2010 the Los Angeles Regional Water Quality Control Board (Regional Board), adopted Resolution No. 10-005 amending the Basin Plan. The amendment updated the bacteria objectives in the Basin Plan by removing the fecal coliform objectives for fresh waters designated for water contact recreation (REC-1 and LREC-1). This action is consistent with EPA's recommendation pursuant to Federal Clean Water Act § 304(a) that Escherichia coli (E. coli) replace fecal coliform as an indicator of the presence of pathogens in fresh water.

In Chapter 3 "Water Quality Objectives" of the Basin Plan, replace Paragraph 2 under "Bacteria, Coliform" on p. 3-3 with the following:

In Marine Waters Designated for Water Contact Recreation (REC-1)

1. Geometric Mean Limits

a. Total coliform density shall not exceed 1,000/100 ml.

b. Fecal coliform density shall not exceed 200/100 ml.

c. Enterococcus density shall not exceed 35/100 ml.

2. Single Sample Limits

a. Total coliform density shall not exceed 10,000/100 ml.

b. Fecal coliform density shall not exceed 400/100 ml.

c. Enterococcus density shall not exceed 104/100 ml.

d. Total coliform density shall not exceed 1,000/100 ml, if the ratio of fecal-to-total coliform exceeds 0.1.

In Fresh Waters Designated for Water Contact Recreation (REC-1)

1. Geometric Mean Limits

E. coli density shall not exceed 126/100 ml.

2. Single Sample Limits

E. coli density shall not exceed 235/100 ml.

In Fresh Waters Designated for Limited Contact Recreation (LREC-1)

1. Geometric Mean Limits

E. coli density shall not exceed 126/100 ml.

2. Single Sample Limits

E. coli density shall not exceed 576/100m1.

Implementation Provisions for Water Contact Recreation Bacteria Objectives

The geometric mean values should be calculated based on a statistically sufficient number of samples (generally not less than 5 samples equally spaced over a 30-day period).

If any of the single sample limits are exceeded, the Regional Board may require repeat sampling on a daily basis until the sample falls below the single sample limit in order to determine the persistence of the exceedance.

When repeat sampling is required because of an exceedance of any one single sample limit, values from all samples collected during that 30-day period shall be used to calculate the geometric mean.

Cal. Code Regs. Tit. 23, § 3937

1. New section summarizing amendments to Basin Plan filed 9-19-2002; amendments adopted by the Los Angeles Regional Water Quality Control Board 10-25-2001 per Resolution No. 01-018. Resolution No. 2002-0142 adopted by State Water Resources Control Board 7-18-2002; approved by OAL and effective 9-19-2002 pursuant to Government Code section 11353 (Register 2002, No. 38).
2. Amendment summarizing amendments to Basin Plan filed 11-1-2011; amendments adopted by the Los Angeles Regional Water Quality Control Board 7-8-2010 per Resolution No. R10-005. Resolution No. 2011-0031 adopted by the State Water Resources Control Board 7-19-2011; approved by OAL and operative 11-1-2011 pursuant to Government Code section 11353 (Register 2011, No. 44).

1. New section summarizing amendments to Basin Plan filed 9-19-2002; amendments adopted by the Los Angeles Regional Water Quality Control Board 10-25-2001 per Resolution No. 01-018. Resolution No. 2002-0142 adopted by State Water Resources Control Board 7-18-2002; approved by OAL and effective 9-19-2002 pursuant to Government Code section 11353 (Register 2002, No. 38).
2. Amendment summarizing amendments to Basin Plan filed 11-1-2011; amendments adopted by the Los Angeles Regional Water Quality Control Board 7-8-2010 per Resolution No. R10-005. Resolution No. 2011-0031 adopted by the State Water Resources Control Board 7-19-2011; approved by OAL and operative 11-1-2011 pursuant to Government Code section 11353 (Register 2011, No. 44).