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West Orange County System

Report prepared by

Golden State Water Company

(800) 999-4033

Public Health Goals - Background

Provisions of the California Health and Safety Code, Section 116470, require public water systems serving more than 10,000 service connections to prepare a report (in plain language) containing information on the “detection” of any contaminants at levels above the Public Health Goals (PHGs) adopted by the State Office of Environmental Health Hazard Assessment (OEHHA) or the additional Maximum Contaminant Level Goals (MCLGs) set by the United States Environmental Protection Agency (USEPA). The first report was required and prepared July 1, 1998 and is required to be revised every three years thereafter.

Golden State Water Company is providing information in conformance with this requirement by providing this revised and updated report at this time. If a constituent was detected in the water supply between 2004 and 2006 at a level exceeding an applicable PHG or MCLG, this report provides health and treatment cost information as required by law.

2007

Report on

Public Health Goals

Regulations and Drinking Water

The USEPA and the California Department of Health Services (CDHS) are responsible for establishing regulations, and setting drinking water standards and goals. These agencies, along with the California Public Utilities Commission (CPUC) set rules and regulations for water systems to follow.

Drinking water goals include MCLGs and PHGs. MCLGs are levels of contaminants in drinking water below which there is no known or expected risk to public health. They are set by the USEPA and allow for a margin of safety. MCLGs are not enforceable drinking water standards. PHGs are water quality goals set by the OEHHA and are recommended target levels and are not required to be met by any public water systems.

Drinking water standards are also known as Maximum Contaminant Levels (MCLs) and Action Levels (ALs). MCLs are the highest level of a contaminant allowed in drinking water. They are set as close to MCLGs and PHGs as are economically and technologically feasible. MCLs are enforceable water quality standards that public water systems must meet. ALs are the concentrations of a contaminant which, if exceeded, triggers treatment or other requirements that the water system must follow.

PHGs and MCLGs are not water quality standards. MCLGs and PHGs are goals identifying extremely small risks. These risks are normally assessed where one person in a million would be at risk to a contaminant. Determinations of health risk at these low levels are frequently theoretical and are based on risk assessments made using assumptions and mathematical extrapolations. Many contaminants are considered to be carcinogenic. The USEPA has set these MCLGs at zero, which cannot be measured by available analytical methods.

The USEPA and CDHS have established Best Available Technologies (BAT) to remove or reduce contaminants to levels at or approaching the PHGs and MCLGs, where technologically feasible. The following information discusses the constituents found in the water served by the water system at or above the MCLGs and PHGs, the established BAT, and the cost estimate to remove the contaminant to the goal levels, where technologically feasible. Please note that accurate cost estimates are difficult, if not impossible, and are highly speculative and theoretical.

Based on the Lead and Copper Rule, GSWC conducted monitoring of lead and copper in water samples collected from wells, the distribution system, and customers’ home taps. All the samples collected from wells and distribution system in 2004 to 2006 contained less than 0.005 milligrams per liter (mg/L) (<0.005 mg/L) of lead and less than 0.05/L (<0.05/L) of copper. There is no MCL for lead or copper. Instead the 90th percentile value of all samples from household taps in the distribution system cannot exceed an Action Level of 0.015 mg/l for lead and 1.3 mg/l for copper. The PHG for lead is 0.002 mg/l. The PHG for copper is 0.17 mg/L. "Action Level" means the concentrations of lead or copper in water which is used to determine the treatment requirements that a water system needs to meet. The results indicate that lead and copper levels in our wells and distribution system are less than the Action Levels and PHGs.

GSWC also analyzed samples from taps inside customer’s houses. Home tap samples are currently collected on a triennial basis. The most recent data were collected in 2004. A total of 58 home tap samples were collected in 2004 with lead levels ranging from non-detection to 0.029 mg/L and copper levels from 0.0045/L to 0.99/L. The 90th percentile level for lead was 0.005 mg/L and for copper was 0.36/L. These values are significantly below the Action Levels per the Lead and Copper Rule, however, the values are above the PHG levels.

The category of health risk for lead is damage to the kidneys or nervous system of humans. The category of health risk for copper is gastrointestinal irritation. Numerical health risk data on lead and copper have not yet been provided by OEHHA, the State agency responsible for providing that information.

Our water system is in full compliance with the Lead and Copper Rule. Based on our extensive sampling, it was determined according to State regulatory requirements that we meet the Action Levels for lead and copper. Therefore, we are deemed by CDHS to have “optimized corrosion control” for our system.

In general, optimizing corrosion control is considered to be the Best Available Technology (BAT) to deal with lead and copper findings. We will continue to monitor our water quality parameters that relate to corrosion control, such as the pH, hardness, alkalinity and total dissolved solids, and will take action if necessary to maintain our system in an “optimized corrosion control” condition.

Since we are meeting the “optimized corrosion control” requirement, it is not prudent to initiate additional corrosion control treatment as it involves the addition of other chemicals and there could be additional water quality issues raised. Therefore, no estimate of cost has been included.

Arsenic has been detected at a levels ranging from non-detect to 9 micrograms per liter (mg/L) in the groundwater supplied to the West Orange County System. The USEPA MCL is 10 mg/L (effective 1/23/06) and the PHG is 4 nanograms per liter (ng/L). Our water system is in full compliance with the federal drinking water standard for arsenic; however the arsenic level in the system at times exceeded the PHG.

The category of health risk associated with arsenic, and the reason that a drinking water standard was adopted for it, is that some people who drink water containing arsenic above the MCL over many years may experience skin damage and circulatory system problems and are at a higher risk of getting cancer. The numerical health risk for the PHG of 4 ng/L is one in a million.

The Best Available Technologies (BATs) for removing arsenic to below the MCL are activated alumina, ion exchange, lime softening, coagulation/filtration and reverse osmosis (RO). The most effective method to consistently remove arsenic to below the PHG is to install RO treatment at the select groundwater and surface water connection sites where the water exceeds the PHG. The cost to install and operate RO removal systems to remove arsenic to below the PHG in West Orange County System would be approximately $4.89 million annually which includes construction and annual operational cost. This translates into a monthly cost of $14.89 per connection ($$ cost /services) for the life of the treatment system.

Bromate

Bromate is a disinfection byproduct when ozone is applied to source water containing naturally occurring bromide. In West Orange Water System, bromate originates from third party imported water that applies ozonation in water treatment. As a result, bromate has been detected at levels up to 7.2 micrograms per liter (mg/L) in the imported surface water supplied to the system. The USEPA MCL is 10 mg/L and the USEPA MCLG is 0 ug/L. Our water system is in full compliance with the federal drinking water standard for bromate, but we have detected bromate in the system above the MCLG level.

The CDHS and USEPA have determined that bromate is a health concern at certain levels of exposure. The category of health risk associated with bromate, and the reason that a drinking water standard was adopted for it, is that some people who drink water containing bromate in excess of the MCL over many years may have an increased risk of getting cancer. The numerical health risk for the MCLG of zero mg/L is zero. CDHS and USEPA set the drinking water standard for bromate at 10 mg/L to reduce the risk of cancer or other adverse health effects.

The Best Available Technology (BAT) for removing bromate to below the MCLG is the control of ozone treatment process to reduce production of bromate. However, in West Orange Water System, bromate is introduced by a third party and has to be to be treated directly. The most effective treatment technique to reduce the bromate levels in the source water to levels below the MCLG is to treat the water by reverse osmosis (RO) at the select sites where the water exceeds the MCLG. The cost to install and operate an RO system to remove bromate to below the MCLG in West Orange County System would be approximately $11.5 million annually which includes construction and annual operational cost. This translates into a monthly cost of $35.08 per connection for the life of the treatment system.

Gross Alpha Particle Activity

Certain minerals are radioactive and may emit a form of radiation known as alpha radiation. Gross alpha particle activity has been detected at levels up to 11.7 picoCuries per liter (pCi/L) in the groundwater and surface water supplied to the West Orange County System. There is no PHG for gross particle activity. The MCLG is 0 pCi/L, and the MCL is 15 pCi/L. The levels detected in our system were below the MCL at all times, but were over the level identified by USEPA as the MCLG.

The CDHS and USEPA, which set drinking water standards, have determined that gross alpha particle activity is a health concern at certain levels of exposure. This radiological constituent is a naturally occurring contaminant in some groundwater and surface water supplies. The category of health risk associated with gross alpha particle activity, and the reason that a drinking water standard was adopted for it, is that some people who drink water containing alpha emitters in excess of the MCL over many years may have an increased risk of getting cancer. The numerical health risk for the MCLG of zero pCi/L is zero. The CDHS and the USEPA set the drinking water standard for gross alpha particle activity at 15 pCi/L in order to reduce the risk of cancer or other adverse health effects.

The Best Available Technology (BAT) identified to treat gross alpha particle activity is reverse osmosis (RO). The most effective method to consistently remove gross alpha particle activity in order to meet the MCLG is to install RO treatment at the select groundwater and surface water connection sites where the water exceeds the MCLG. The cost to install and operate RO removal systems to remove gross alpha particle activity to the MCLG in our West Orange County System would be approximately $4.01 million annually which includes construction and annual operational cost. This translates into a monthly cost of $12.20 per connection ($$ cost /services) for the life of the treatment system.

Uranium

GSWC conducted monitoring of uranium in water samples collected from wells. All the samples collected from wells in three consecutive years of 2004 to 2006 contained less than or equal to 11.7 pCi/L of uranium with an average of 10.0 pCi/L. The USEPA has established a MCL for natural uranium of 20 pCi/L and a MCLG of 0 pCi/L. The State of California has a MCL for uranium of 20 pCi/L and a PHG of 0.43 pCi/L based on the numerical health risk of one in a million. The health risks associated with long term drinking intake at levels above MCL are the increased risk of getting cancer and potential kidney problem.

This radiological constituent is a naturally occurring contaminant in some groundwater and surface water supplies. Uranium occurs as a trace element in many types of rocks. Because its abundance on geological formations varies from place to place, uranium is a highly variable source of contamination in drinking water.

The Best Available Technologies (BATs) identified to treat uranium are ion exchange, reverse osmosis (RO), lime softening, and coagulation/filtration. The most effective and economical treatment system is to use RO treatment at select plant sites. The cost estimate for reducing the concentration of uranium to below the PHG level is approximately $3.59 million annually which includes construction and annual operational cost, or $10.91 per customer per month for the life of the treatment system.

Total coliform bacteria have been present in maximum of 2.2 percent in monthly samples collected from the distribution system with repeat samples being consistently negative. The 2.2 percent is the highest monthly percentage over the 36-month period from 2004 to 2006. GSWC’s West Orange County System collects between 100 and 125 samples every month at points throughout the water distribution system that are analyzed for total coliforms. Total coliform bacteria were only present in 12 samples of the 3,938 samples collected during the 36 months from 2004 through 2006. The MCL for total coliform is 5 percent of monthly samples and the MCLG is 0 percent for monthly samples. The total coliform bacteria percentage levels for water in the distribution system were below the MCL at all times, but at times were over the MCLG.

The CDHS and USEPA, which set drinking water standards, have determined that the presence of total coliform is a possible health concern. Coliforms are common in the environment and are generally not harmful themselves. The presence of these bacteria in drinking water, however, generally is a result of a problem with water treatment or the pipes that distribute the water, and indicates that the water may be contaminated with organisms that can cause disease. Disease symptoms may include diarrhea, cramps, nausea, and possibly jaundice, and any associated headaches and fatigue. These symptoms, however, are not just associated with disease causing organisms in drinking water, but also may be caused by a number of factors other than your drinking water.

Because total coliform is only an indicator of the potential presence of pathogens, it is not possible to state a specific numerical health risk. The CDHS has set an enforceable drinking water standard for total coliform to reduce the risk of these adverse health effects. Under this standard, no more than 5 percent of the samples collected during a month can contain these bacteria. Drinking water that meets this standard is usually not associated with a health risk from disease causing bacteria and should be considered safe.

The CDHS lists four operating and maintenance conditions as the Best Available Technology (BAT) for protection against microbiological contaminants. These conditions are practiced by the West Orange County System, and are as follows:

• Protection of wells from coliform contamination by appropriate placement and construction;

• Maintenance of a disinfectant residual throughout the distribution system;

• Proper maintenance of the distribution system; and

• Filtration and disinfection of approved surface water, and disinfection of groundwater.