The California Water Boards' Annual Performance Report - Fiscal Year 2015-16

PLAN AND ASSESS: SEWAGE SPILLS

GROUP:

SANITARY SEWER OVERFLOWS
(Collection Systems)

MEASURE:

SIZE OF SEWER SYSTEMS
SEWAGE SPILLS

MESSAGE:

59 percent of regulated facilities did not report a sewage spill in FY 2015-16. Of the spills that did occur, 40 percent of the sewage spilled reached surface waters.

*KEY STATISTICS FOR FY 2015-16*
Facilities reporting no spills:	645
Facilities reporting 6 or more spills:	115

MEASUREMENTS - Data last updated on: 09-20-2016 (4:56 pm)

Region	Facilities Regulated Under SSO Program	Facilities With No Spills Reported	Total Sewage Spill Events During FY 13-14	Number of Facilities Reporting One Sewage Spill	Gallons Spilled for Facilities with One SSO	Number of Facilities Reporting 2 to 5 SSOs	Gallons Spilled for Facilities Reporting 2 to 5 SSOs	Number of Facilities Reporting 6 or More SSOs	Gallons Spilled for Facilities Reporting 6 or More SSOs
1	70	43	65	14	19,125	10	23,766	3	3,700
2	133	44	1,015	17	5,792	28	876,008	44	1,852,990
3	105	64	158	12	89,216	19	81,361	10	158,150
4	144	74	365	25	474,913	32	168,148	13	263,491
5F	154	116	2,000	21	419,154	12	225,866	5	113,731
5R	50	40	0	5	188,026	3	2,960	2	28,867
5S	185	108	0	28	77,421	30	167,353	19	485,424
6A	22	16	73	1	500	3	2,970	2	548
6B	49	36	0	6	189,053	6	11,518,726	1	3,940
7	32	26	27	3	1,300	2	70,050	1	4,025
8	89	50	135	11	7,985	21	279,489	7	67,235
9	62	28	143	14	51,315	12	191,464	8	6,853,304
TOTAL	1,095	645	3,981	157	1,523,800	178	13,608,161	115	9,835,405

Region	Volume of Sewage Spilled	Volume Reaching Surface Water	Percent Reaching Surface Water
1	46,591	6,042	13%
2	2,734,790	1,775,756	65%
3	328,727	43,943	13%
4	906,552	682,897	75%
5F	758,751	46,750	6%
5R	219,853	200,316	91%
5S	730,198	357,430	49%
6A	4,018	10	0%
6B	11,711,719	54,406	0%
7	75,375	0	0%
8	354,709	32,974	9%
9	7,096,083	6,844,272	96%
TOTAL	24,967,366	10,044,796	40%

WHAT THE MEASURE IS SHOWING

In Fiscal Year (FY) 2015-16, 115 facilities regulated under the SSO Program reported 39 percent of the total volume of sewage spilled statewide. Of the remaining facilities regulated under the SSO Program, 645 of the 1,095 collection systems regulated (59 percent) did not report any spills during the FY.

WHY THIS MEASURE IS IMPORTANT

SSOs often contain high levels of suspended solids, pathogenic organisms, toxic pollutants, nutrients, oil, and grease. Typical consequences of SSOs include the closure of beaches and other recreational areas, inundated properties, and polluted rivers and streams. This measure tracks the reporting required by the Statewide Sanitary Sewer Order and will help to determine if the sewer system management plans (SSMP), also required by the order, are contributing to a reduction in the number of SSO events.

TECHNICAL CONSIDERATIONS

Data source: CIWQS. Period July 1, 2015 to June 30, 2016.
Unit of Measure: Average Number of Spills per 100 miles: Measures the number of sewer overflows per 100 miles of sewer lines. Average Volume of Spills per 100 miles: Measures the volume in gallons of sewer overflows per 100 miles of sewer lines.
Data Definitions: Sanitary Sewer: A pipe or conduit (sewer) intended to carry wastewater or water-borne wastes from homes, businesses, and industries to the POTW. Sanitary Sewer Overflows (SSO): Untreated or partially treated sewage overflows from a sanitary sewer collection system.
References: Information on the Sanitary Sewer Overflow Reduction Program
The Sanitary Sewer Overflows Incident Map
The Interactive SSO Report

GLOSSARY

Sanitary Sewer Overflow

A sanitary sewer overflow (SSO) is any overflow, spill, release, discharge or diversion of untreated or partially treated wastewater from a sanitary sewer system. SSOs do not include overflows from blockages or other problems within a privately owned lateral.

Sanitary Sewer Overflow Reduction Program

In May, 2006, the State Water Board adopted a Statewide Sanitary Sewer Order (ORDER NO. 2006-0003-DWQ) to address the issue of SSOs in a consistent and uniform manner statewide. Through the order, California became the first state in the nation to implement a program focused on the regulation of sanitary sewer systems. Sanitary sewer system agencies covered under the order, referred to as Enrollees, are required to report all SSOs for which their agency has responsibility into the State Water Board’s SSO database. Enrollees are also able to report sewage discharges from privately owned laterals or collection systems, for which the Enrollee has knowledge of the event but is not responsible, on a voluntary basis.

( Page last updated: 10/11/16 )