SunnyvaleRTC

CITY OF SUNNYVALE

PUBLIC HEALTH GOALS REPORT

BACKGROUND

The California Health and Safety Code, section 116470(b) (see Attachment 1) requires public water systems serving more than 10,000 service connections to prepare a report by July 1, 2004 if water quality monitoring results over the past 3 years indicate levels that exceed any California Public Health Goals (PHGs) and/or federal Maximum Contaminant Level Goals (MCLGs). PHGs are non-enforceable goals established by the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA). MCLGs are goals that are adopted by USEPA, and only come into play if there is no California PHG. PHGs may not be more lenient that MCLGs.

Only constituents that have a California primary drinking water standard and for which either a PHG or MCLG has been set are to be addressed in the report. Attachment 2 contains a list of the regulated constituents for which the City exceeded the goals and their respective PHGs or MCLGs. There were only two (total coliform count, and copper), and they were only minimally over the PHG/MCLG, well below any action level.

If a constituent was detected by a water supplier between 2001 and 2003 at a level exceeding an applicable PHG or MCLG, the PHG reports are to provide the information required by the law. The required information includes:

· the numerical public health risk associated with the enforced Maximum Contaminant Level (MCL) and the PHG or MCLG;

· the category or type of risk to health that could be associated with each constituent;

· the best treatment technology available that could be used to reduce the constituent level; and

· an estimate of the cost to install that treatment if it is appropriate and feasible.

PHG/MCLG vs. MCL

PHGs are set by OEHHA (and MCLGs by USEPA) based solely on public health risk considerations. MCLs are set by USEPA or the California Department of Health Services (CDHS) as the level which is required to be met in water systems. Violations of MCLs can result in fines, abatement orders, or closure of facilities. When the USEPA, or the CDHS, adopts an MCL, they take into account such factors as (1) analytical methodologies, (2) effectiveness of available treatment technologies, and (3) benefits and costs. PHGs (and MCLGs) are not enforceable and are not required to be met by any public water system.

Water Quality Data Review for this Report

Water quality data collected by the City of Sunnyvale during 2001, 2002 and 2003 for purposes of determining compliance with drinking water standards were reviewed in order to prepare this PHG report. This data was all summarized in our 2001, 2002, and 2003 Annual Water Quality Reports, also known as Consumer Confidence Reports (CCRs), that were distributed to all of our customers, generally included in the summer issue of the Quarterly Report.

Guidelines Followed for Preparation of this Report

The Association of California Water Agencies (ACWA) formed a workgroup which prepared guidelines for water utilities to use in preparing these newly required reports. The ACWA guidelines were used in the preparation of our report.

Best Available Treatment Technology and Cost Estimates

Both USEPA and CDHS adopt Best Available Technologies (BATs), which are the best known methods of reducing contaminant levels below the MCL. While a BAT may identify a process that can reduce the presence of a contaminant, the cost of implementation can be a major factor in deciding whether or not to adopt the process. For a system that is in compliance with MCL levels, cost considerations must be a factor. Striving to keep contaminants below PHG/MCLG levels must be evaluated with costs in mind.

Costs were estimated for the implementation of BATs for each constituent exceeding PHGs or MCLGs. The PHGs and MCLGs are set much lower than the MCL, and it is not always possible or feasible to determine what treatment is needed to further reduce a constituent to or below the PHG or MCLG. In some cases, such as when the MCLG or PHG is set at zero, there may not be commercially available technology to reach that level. The issue is further complicated because it is often not possible to verify by analytical means that the contaminant has been totally eliminated. In some cases, installing a treatment to try and further reduce very low levels of one constituent may have adverse effects on other aspects of water quality. This report presents the required cost estimates to implement the BATs to reduce a contaminant to a level at or below the PHG/MCLG.

CONSTITUENTS DETECTED THAT EXCEED A PHG OR AN MCLG

In reviewing water quality monitoring data collected during 2001, 2002 and 2003, City of Sunnyvale staff have concluded that a PHG report is required that addresses the following contaminants:

1. coliform bacteria, and

2. copper.

The following section presents a discussion of the two constituents that were detected in one or more of our drinking water sources at levels above the PHG/MCLG.

Coliform Bacteria

In 1989 EPA developed the Total Coliform Rule (TCR). The MCL for total coliforms is five percent (5%) positive samples of all samples per month. The MCLG is zero (there is no PHG for coliform bacteria).

The reason for the coliform drinking water standard is to minimize the possibility of the water containing pathogens (e.g., fecal contamination). Pathogens are microorganisms that cause disease if ingested. Coliform bacteria is an indicator organism that is not generally considered harmful, but is used to identify the potential presence of pathogens in the water. It is not unusual for a system to have an occasional positive sample. A positive sample serves as a trigger to prompt further investigation into the presence of other organisms, requiring additional sampling to be done immediately after it is discovered.

The monitoring of a non-harmful contaminant (coliform bacteria) to indicate the possible presence of harmful contaminants makes for an inexact, but generally conservative, process to detect harmful pathogens. Therefore, it is not possible to state a specific numerical health risk associated with a given level of coliform bacteria. EPA normally sets MCLGs “at a level where no known or anticipated adverse effects on persons would occur.” When EPA published the final TCR they stated that it was not possible to determine such a level with coliform sampling. The absence of coliform bacteria is therefore the goal, and when that goal is not achieved, follow-up testing verifies whether an actual pathogen is present.

BAT Contained in the TCR

The Total Coliform Rule identifies the following as BAT for total coliforms:

1. Protection of wells from contamination by appropriate placement and construction;

2. Maintenance of a disinfectant residual throughout the distribution system;

3. Proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, and continual maintenance of positive water pressure in all parts of the distribution system;

4. Filtration and/or disinfection of surface water as described in Subpart H, or disinfection of ground water using strong oxidants such as chlorine, chlorine dioxide, or ozone; or

5. The development and implementation of an EPA-approved State Wellhead Protection Program under section 1428 of the SDWA.

Sunnyvale has implemented all of the above actions or processes, or obtains water from suppliers who practice these processes (such as filtration and chloramination).

Sunnyvale TCR Monitoring Results

Each month the City of Sunnyvale collects 184 samples from sites located throughout the distribution system that are analyzed for the presence of coliform bacteria. If a positive sample is found, follow-up sampling is done for more specific indicators of fecal contamination.

During 2003, the City of Sunnyvale had a monthly average of 0.6% positive samples for coliform bacteria. All instances where a positive sample was initially found indicated an absence of pathogens in follow-up samples. The data indicated that these were isolated incidents, and the quality of the water in the distribution system was never compromised.

No Additional Actions for Coliform Bacteria Are Recommended

The Total Coliform Rule identifies the following as BAT for total coliform:

1. Protection of wells from contamination by appropriate placement and construction;

2. Maintenance of a disinfectant residual throughout the distribution system;

4. Filtration and/or disinfection of surface water as described in Subpart H, or disinfection of ground water using strong oxidants such as chlorine, chlorine dioxide, or ozone; or

5. The development and implementation of an EPA-approved State Wellhead Protection Program under section 1428 of the SDWA.

The City of Sunnyvale works closely with our regional water suppliers, the Santa Clara Valley Water District (SCVWD) and the San Francisco Public Utilities Commission (SFPUC). SFPUC has recently instituted new disinfection procedures for their Hetch-Hetchy supply to provide a chloramine disinfectant residual. This change on the part of SFPUC was carefully studied before it was implemented. The SCVWD has been providing water with a chloramine residual since 1983.

Other measures and programs that help protect the microbiological quality of the drinking water served by the City of Sunnyvale include:

· flushing of all distribution system dead-ends every year;

· flushing of all hydrants every two years;

· cross-connection control program;

· monitoring of a disinfectant residual throughout the distribution system;

· ongoing microbiological monitoring and surveillance program of all groundwater sources and the distribution system;

· program to clean all distribution system tanks every 5 years; and

· maintenance of positive pressures throughout the distribution system.

No Additional Actions for Coliform Bacteria Are Recommended

No additional actions are recommended at this time for coliform bacteria.

Copper

Copper is regulated in drinking water as part of the Lead and Copper Rule (LCR) published by EPA in 1991. Rather than comply with a specific MCL, the LCR requires public water systems to complete a series of steps. These steps include: materials-evaluation of the distribution system, identification of high priority home-tap samples, home-tap monitoring, and evaluation of water quality parameters that may cause a water to be corrosive, such as elevated phosphate levels. The ultimate goal of these steps on the part of the utility is to identify and implement an “optimal corrosion-control treatment” for the given system.

The PHG for copper is 0.17 mg/L. There is no MCL for copper. There is an Action Level of 1.3 mg/L (1300 ppb). After completing each round of home-tap sampling, the utility identifies the 90^th percentile value from all of the sample results and compares that level to the Action Level.

Copper is an essential nutrient. The type of health risk associated with elevated levels of copper is gastrointestinal irritation. No numerical health risk data on copper is available from OEHHA, the State agency responsible for providing that information.

During 2002 the City of Sunnyvale conducted its triennial LCR sampling at 50 selected homeowner taps. The results for the monitoring conducted during 2002 indicated that the 90^th percentile for copper was 0.210 mg/l. While these results indicate that the 90^th percentile value for copper for this test still exceeded the PHG, it was well below the Action Level.

Best Available Technology for Copper Elimination and How It Is Applied By Sunnyvale

In general, optimizing corrosion control is considered to be the best available technology to deal with corrosion issues and with any lead or copper findings. In 1992-1993 the City of Sunnyvale participated in the SCVWD corrosion control study with other water purveyors located in the Santa Clara Valley. The SCVWD water used by the City is treated for corrosion control with the addition of zinc orthophosphate at the Rinconada Water Treatment Plant. The SCVWD corrosion control study was completed in 1994 and sent to USEPA in June 1994. The study recommended that no additional corrosion control treatment is needed for the City of Sunnyvale.

The City of Sunnyvale’s water system is in full compliance with all federal and state requirements under the LCR. Through our ongoing monitoring program, as well as the efforts of SFPUC and SCVWD, the City of Sunnyvale has been deemed by DHS to have “optimized corrosion control,” as determined by the Lead and Copper Rule promulgated by EPA.

No Additional Action for Copper is Recommended

As required by the CDHS, the City of Sunnyvale will continue to monitor for pH and phosphate levels in the distribution system to continue to demonstrate that the system is maintaining optimal corrosion control conditions. In response to a CDHS request the City of Sunnyvale will accelerate its next round of home-tap sampling, and will conduct that monitoring during 2004 instead of 2005, when it would normally be required.

No additional action is recommended for the City of Sunnyvale regarding copper.

SUMMARY AND CONCLUSION

The drinking water for the City of Sunnyvale meets all standards established by California Department of Health Services and USEPA to protect public health. No additional treatment is recommended in an effort to decrease the incidence of total coliform in system water testing. Similarly for copper, the City of Sunnyvale recommends no additional treatment at this time to lower the levels of copper. There are no clear benefits to be derived from expensive efforts to further reduce the levels of these contaminants. Both contaminants are well below the level of concern, and elimination of either may be impossible. Therefore, no actions are proposed for either coliform bacteria or copper.

Attachments:

1. Excerpt from Calif Health & Safety Code: Section 116470 (b)

2. Table of Regulated Constituents with MCLs, PHGs or MCLGs (.doc format)