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Drinking Water Quality Report

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Water Quality Report for City of Tumwater Water System

The City of Tumwater's annual Drinking Water Quality report details water quality sampling results collected during the previous five years. The dedicated City staff who operate and maintain the water system continually strive to ensure that the water delivered to your tap is of the highest quality possible. 

All of Tumwater's drinking water comes from groundwater sources. To access this groundwater, the City operates eleven wells in three different well fields. The Palermo wellfield is located in the Deschutes River valley; the Bush wellfield is located near George Washington Bush Middle School; and the Port wellfield is located in the vicinity of City Hall. Since all three sites are in different locations, they require slightly different processes to create clean drinking water. Water taken from the Bush and Palermo wellfields are aerated for corrosion control and to eliminate the potential for volatile organic compound (VOC) contamination. Chlorine is added to all sources to control naturally occurring bacteria. In addition, the Tumwater system has two interconnections with the City of Olympia's water system and with the Lakeland Manor water systems. These two interconnections serve as supplementals to the drinking water supply in the event of an emergency. The City of Tumwater also maintains an emergency back-up source at the Tumwater Valley Municipal Golf Course.



What we look for in your water

Drinking water flows across the land and through the ground before being pumped into the drinking water distribution system. As the water moves through the ground it dissolves naturally occurring minerals, and can pick up additional substances due to the presence of animal or human activities. The City tests for the following contaminants at regular intervals to ensure that drinking water is clean and safe:

Microbial contaminants, such as viruses, parasites, and bacteria that may come from sewage treatment plants, septic systems, agricultural livestock operations, or wildlife.

Inorganic contaminants, such as salts and metals, which can occur naturally or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming.

Pesticides and herbicides, which may come from various sources such as agriculture, urban stormwater runoff, and residential uses.

Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by-products of industrial processes and petroleum production. They can also come from gas stations, urban stormwater runoff, and septic systems.

Radioactive contaminants, which can occur naturally or result from oil and gas production and mining activities.

For information about how the City protects your groundwater and to see our most recent Wellhead Protection Plan visit our wellhead protection page.

Water Quality Results from 2014 - 2019

Source Water Sampling: The following three tables detail water quality results from samples collected at the City's wells.

 Primary drinking water standards regulated by EPA to protect public health
 Contaminant Units  Highest level allowed (MCL)  Goal not to exceed (MCLG)  Amount present in your water Year detected  Source 
 Maximum  Range
 Nitrate ppm  10.00  10.00  1.480  ND - 1.480  2019 Naturally-occurring, found in groundwater, typically from agricultural runoff
Barium ppm  2.000  20.000  0.005  0.002- 0.005  2019 Erosion of natural deposits
 Arsenic ppm   0.010  0.000  0.001 NA-0.001  2019  Erosion of natural deposits; runoff from waste
 Gross Beta  pCi/L  4.000 mrem/yr  NA  2.730  NA-2.730  2015  Decay of naturally radioactive deposits and/or man-made radioactive materials.
 Radium 228  pCi/L  5  NA  2.780  NA-2.780  2015  Decay of naturally radioactive deposits and/or man-made radioactive materials.


Secondary drinking water standards regulated by EPA for aesthetics (taste, color, etc.) 
 Contaminant  Units  Goal not to exceed (SMCL)  Amount present in your water  Year detected Source 
 Maximum  Range
Chloride  ppm 250.0 5.300  2.500-5.300   2019 Naturally-occurring 
Conductivity  Umhos/cm  700.0  202.0 NA -202.0  2018 Naturally-occurring 
Iron  ppm 0.3 00  0.190 ND-0.190  2019 Naturally-occurring 
 Manganese ppm 0.050 0.011  ND-0.011  2019 Naturally-occurring 
Sulfate  ppm 250.0 5.200 3.200-5.200 2019 Naturally-occurring 
Total Dissolved Solids  ppm 500.0 129.0 100.0-129.0 2019 Naturally-occurring 
Zinc  ppm 5 .000 0.005   ND-0.005 2019 Naturally-occurring 

 Additional monitoring required by the State of Washington
 Contaminant  Units  Goal not to exceed  Amount Present in Your Water  Year detected Source 
 Maximum  Range
 Hardness ppm  NA  69.70  41.70-69.70  2019  Naturally-occurring
 Sodium ppm  NA  7.080  5.320-7.080  2019  Naturally-occurring
 Turbidity  NTU  1.000  0.150  ND-0.150  2019  Naturally-occurring


Distribution System Sampling: The following table details water quality results from samples collected in the city's distribution system pipes.

 Primary drinking water standards regulated by EPA to protect public health
 Contaminant  Units  Highest level allowed (MCL accept where indicated) Goal not to exceed (MCLG accept where indicated)   Amount present in your water  Year detected Source 
Max  Range
Chlorine residual  4.000 (MRDL)  4.000 (MRDL)  0..650  0.200-0.650  2019  Water additive used to control bacteria
 Haloacetic Acids (HAA5)  ppm 0.060   NA  0.006  0001-0.006  2019  Byproduct of drinking water disinfection
 Total Trihalomethanes (TTHM)  ppm  0.080  NA  0.005 ND-0.005   2019  Byproduct of drinking water disinfection

Tap Sampling: The following table details water quality results from samples collected at our customer's taps.

 Primary drinking water standards regulated by the EPA to protect public health
 Contaminant  Units  Action level  Goal not to exceed (MCLG)  2019 results* Homes exceeding the action level Source 
 Copper  ppm  1.300  1.300  0.212  ND-0.212  Corrosion of household plumbing, 0 out of 60 samples.
 Lead  ppm  0.015  0.000  0.000  ND-0.000  Corrosion of household plumbing, 1 out of 60 samples

 *90th percentile



90th Percentile: 90 percent of the samples were less than the values shown.   

Action Level: The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.

Aeration: Drinking water treatment that uses air to dissolve gases or volatile compounds and raise the pH of drinking water. 

Contaminant: Contaminants, as seen in this table, are not all "bad". Contaminants are anything found in your water other than hydrogen and oxygen, which make up water, and can be both healthy and unhealthy, depending on the particular substance and quantity.

Distribution System: Water supply network that delivers potable water from a treatment plant or wells to water consumers. 

EPA: United States Environmental Protection Agency.

Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.

Maximum Contaminant Level Goal (MCLG): The level of a contaminant in your drinking water is below the Maximum Contaminant Level Goal (MCLG) number indicated, then there is no know or expected risk to your health. 

Maximum Residual Disinfectant Level (MRDL): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that the 2addition of a disinfectant is necessary for control of microbial contaminants.

Maximum Residual Disinfectant Level Goal (MRDLG): The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.

NA: Not Applicable. There is no unit of measurement, only absence or presence of. 

ND: Not Detected. The contaminant was not detected during sampling events.

NTU: Nephelometric Turbidity Unit

ppm: one part per million = 1 mg/L

Secondary Maximum Contaminant Level (SMCL):  Non-enforceable guidelines regarding chemicals that may cause cosmetic or aesthetic effects in drinking water. EPA recommends these secondary standards but does not require water-supply systems to comply.

TT: Treatment Technique: Enforceable procedure or level of technological performance which public water systems must follow to ensure control of a contaminant. 

Additional water quality information

The frequency that we sample our sources is determined by the Washington State Department of Health (DOH). DOH has determined that the level of risk in our system is low for certain contaminants, and granted the City waivers to sample less frequently. The table below describes the sampling frequency for our sources and where waivers have been given.

 Contaminant or Contaminant Group  Source  Sampling Frequency
 Nitrate All  Yearly
 Pesticides All  Every 3 years*
 Soil Fumigants  All  Every 3 years*
 Complete Inorganic (IOC)  All  Every 9 years*
 Herbicides  All  Every 9 years*
 Volatile Organic Compounds (VOC)  Palermo well field  Every 3 years
 Wells 9 and 10 (Port well field)  Every 3 years
 Wells 11 and 15 (Port well field)  Every 6 years*
 Bush well field  Every 6 years*
 Gross Alpha and Radium 228  All  Every 6 years


 *Waiver provided by DOH

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the EPA’s Safe Drinking Water Hotline (1-800-426-4791). 

To ensure that tap water is safe to drink, DOH and EPA prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. The Food and Drug Administration (FDA) and the Washington Department of Agriculture regulations establish limits for contaminants in bottled water that must provide the same protection for public health.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons, such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA and CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline 1(800) 426-4791.

In Washington State, lead in drinking water comes primarily from materials and components used in household plumbing. The more time water has been sitting in pipes, the more dissolved metals, such as lead, it may contain. Elevated levels of lead can cause serious health problems, especially in pregnant women and young children. To help reduce potential exposure to lead: Any drinking water tap that has not been used for six hours or more, flush water through the tap until the water is noticeably colder before using for drinking or cooking. You can use the flushed water for watering plants, washing dishes, or general cleaning. Only use water from the cold-water tap for drinking, cooking, and especially for making baby formula. Hot water is likely to contain higher levels of lead. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water is available from EPA’s Safe Drinking Water Hotline at 1(800) 426-4791, or online at

Tier 3 Monitoring Violation: We are required to report the results of your drinking water for total coliform on a regular basis. Results of the regular monitoring are an indicator of whether or not your drinking water meets health standards. During the month of January 2020, we did not report the total coliform results to the state in a timely manner. While we took samples that month, we did not notify the state as quickly as we should have. We submitted them upon becoming aware of the missed deadline. We are no longer in violation and there is nothing you need to do at this time. 

Past Water Quality Reports

2019 Water Quality Report pdf-icon-sm

2018 Water Quality Report pdf-icon-sm

2017 Water Quality Report pdf-icon-sm

2016 Water Quality Report pdf-icon-sm

2015 Water Quality Report pdf-icon-sm

2014 Water Resources | Programs & Utilities pdf-icon-sm

2013 Water Quality Report  pdf-icon-sm

2012 Water Quality Report  pdf-icon-sm

Learn more...

For more information about groundwater, drinking water and possible contaminants including cryptosporidium and other microbial contaminants, and potential health effects, visit, or call the EPA Safe Drinking Water Hotline at 1(800) 426-4791.