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Thurston County, Washington

The content on the Thurston County website is currently provided in English. We are providing the “Translation” for approximately 10 languages. The goal of the translation is to provide visitors with limited English proficiency to access information on the website in other languages. The translations do not translate all types of documents, and it may not give you an exact translation all the time. The translations are made through an automated process, which may not result in accurate or precise translations, particularly of technical and legal terminology.

Public Health and Social Services


Algae is a large, diverse group of photosynthetic plants, from incredibly tiny diatoms that makeup the foundation of our food webs to giant kelp forests of the sea. Light, water temperature and movement, and nutrients — particularly phosphorous and occasionally nitrogen — determine and can trigger algal growth. Like other plants, algae have a pigment called chlorophyll that is used to turn sunlight into food and can be found in all types of water!

When there is a substantial bloom and/or the type of algae is toxin producing, then this event is considered a Harmful Algae Bloom. Learn more about these events below.

When there is algae bloom present or you suspect that an algae bloom is occurring, we recommend extra precautions be taken to avoid the health risks posed by potential toxins.

  • Do not drink the lake water.
  • Avoid contact with water containing algae. Do not swim or water ski in areas with algae.

  • Keep pets and livestock away from areas where algae blooms are present.

  • When fishing, use only catch-and-release of any fish caught during an algae bloom.

  • Do not eat fish that come from the lake during an algae bloom.

  • Avoid areas of scum when boating.
green algae covering lake

Current Thurston County Algae Advisories

There are no algae advisories at this time. 

Reporting an Algae Bloom 

Environmental Health Issue Reporting 

Risks of Algae

When there is an algae bloom present or you suspect that an algae bloom is occurring, we recommend extra precautions be taken to avoid the health risks posed by potential toxins.

  • Do not drink the lake water.
  • Avoid contact with water containing algae. Do not swim or water ski in areas with algae.

  • Keep pets and livestock away from areas where algae blooms are present.

  • When fishing, use only catch-and-release of any fish caught during an algae bloom.

  • Do not eat fish that come from the lake during an algae bloom.

  • Avoid areas of scum when boating.

You can learn more about toxic algae blooms and health risks at or call 360-867-2626.

Reporting an Algae Bloom 

Environmental Health Issue Reporting 

Lake Advisory Email Sign Up

Please indicate which lake(s) on the list you would like to receive updates on.

Lake Advisory Email 

Harmful Algal Blooms (HABs) are substantial growths of algae and/or growth of toxin producing algae in a waterbody. Blooms most commonly occur in the warmer months, when light, temperature and nutrients in the water are optimal for growth, however blooms can occur at any time of year and not all are toxic. The bloom may disappear after one to two weeks, but if conditions are right, another bloom can occur and quickly replace the previous one and continue for several months. These blooms can cause significant harm to living creatures and disrupt the economic and social life of humans.

Climate change and increased nutrient pollution are causing these events to be more frequent, severe, and to occur in locations not previously seen. The effort of all communities will be needed to lessen this issue.

Eutrophication – This term describes a process that occurs when an environment becomes enriched in nutrients, causing a growth of algal blooms and plants in the waterbody. As the excessive number of algae and plants die off, oxygen becomes depleted and carbon dioxide is produced. The consumption of oxygen can create zones of water that are inhospitable for aquatic life. In other words, these species must be able to leave these zones, or die.

Toxins – The understanding of effects and development of action levels for algal toxins is an emerging development.  Just as there are a variety of algal types, there are also many toxins to be studied and examined. It is necessary to note that not all algae types produce a toxin. With that said, Harmful Algal Blooms can cause sever health effects in humans and wildlife. Below is a list of commonly found algal blooms and associated toxins.

Too Dense – When a bloom becomes extremely dense there are a variety of impacts to life, the environment, and the economy. These impacts could include the following: Prevent sunlight from entering the water column, clog gills, cause fishing and shellfish loss, impact the health of humans and wildlife, negatively impact tourism, increase the treatment cost of water, and even lower waterfront property values.


Water Type



Target Tissue

Health Effects

Alexandrium sp.




Nerves and Muscles

Paralytic shellfish poisoning, paralysis, death

Karenia brevis




Nervous Syste

Respiratory System

Gastrointestinal illness, muscle cramps, seizures, paralysis

Respiratory problems, especially for asthmatics




Domoic acid

Nervous System

Amnesiac shellfish poisoning, vomiting, diarrhea, confusion, seizures, permanent short-term memory loss, or death






Gastrointestinal illness, liver damage

It is not possible to know if an algal bloom is harmful just from visually looking at it. Only laboratory tests can determine if an algae bloom is toxic. Protect yourself and others by being cautious and by learning to identify visual algae blooms. Below you can find a list of characteristics to look for and a few visual examples to help you identify a bloom:

Watercolor: Blue, Green, Brown, Yellow, Orange, Red

Visual Appearance: Foam, Mats, Scum, Spilled Paint

Reducing nutrient pollution to waterbodies is the key action you can take to reduce these blooms. A few ways are detailed below:

  • Pick up after your pets and encourage others to do the same.
  • Prevent livestock from entering the water and agriculture waste runoff.
  • Reduce fertilizers and apply them at times to avoid runoff.
  • Maintain your septic system.
  • Plant native species to reduce erosion and runoff.
  • Utilize water efficient equipment to reduce wastewater generated.
  • Educate your community!

Across the county you may come across signs detailing the algae sampling results from our lake program. These signs are posted for the safety and wellbeing of all residents and visitors of Thurston County. Follow the stated information on the signs to protect your health. A visual of the signs you may see is provided below.



There are very high levels of toxins in the lake.  The lake is closed.  Keep out of the lake.  Do not swim, wade, fish, or boat. Do not drink the lake water or use it for dishes, laundry or other household uses.

Danger Algae Sign



Algae toxins have been detected above the advisory level in the lake.  The lake is unsafe for people and pets.  Do not swim or water ski, do not drink the lake water, keep children, pets and livestock away from the water.  It Is okay to boat, avoiding areas of scum.  Clean fish well and discard guts – it is safest to catch and release.

Warning Algae Sign



Take caution and avoid blooms if present. These signs are posted at all public boat launches and stay up year-round. These are provided as educational awareness to protect public health.

Caution Algae Sign

Animal Safety


These signs are provided as requested. Pets are at a higher risk to ingest toxic algae and these signs bring awareness and tips to protect your family members. 

Animal Safety Algae Sign
  • Children usually weigh less than adults, so a smaller amount of the toxin may make them sick and the toxin may affect a child's liver or central nervous system more than it would an adults. Children may also be at greater risk than adults because they may not be aware of any health risks due to a toxic bloom and may swallow water accidentally while swimming.
  • People who fish may have a higher risk. Toxins can accumulate in fish tissues, especially in the viscera (liver, kidneys, etc.). Concentrations in the tissues would depend on the bloom and toxin severity where the fish was caught.
  • Pets and wildlife are likely to ingest algae when they drink water or lick their fur after swimming in a lake or pond with toxic algae. If toxins are being produced at the time animals can become very ill and even die. Dogs can be exposed to toxins by licking their fur after swimming. Don't let pets or livestock swim or drink in areas where there is a scum or mat of algae on the water. If they do swim in such areas, rinse them off as soon as you can.

Swimming & Boating

For additional park info, visit Thurston County Parks.

Kenneydell County Park

Nearly 1,000 feet of shoreline on Black Lake with reservable shelters, from Hwy 101, take Black Lake Blvd south to Black Lake Belmore Rd, continue south to 66th Ave W, then west to the park.

Kenneydell Picture

Long Lake Park

Lacey city park with a great swimming beach and volleyball courts, located off Carpenter Rd near the county fairgrounds.

Long Lake Picture

Millersylvania State Park

An 842-acre camping park on Deep Lake with 3,300 feet of shoreline, exit #95 east and follow signs to the park. For additional park info, see the Washington State Parks Department.

Millersylvania State Park

Tenino Quarry Pool

Located behind the old Tenino Stone Company in downtown Tenino at 319 Park Ave W. See City of Tenino

Tenino Quarry Picture

Woodruff Park Spray-ground

The spray-ground is located on Harrison Ave and is open 11:00 am - 08:00 pm from June 1 to Sept. 1

Woodruff Park splashpad


Heritage Park Fountain

"Olympia's swimming pool" located in the heart of downtown Olympia outside the Capitol Building.

Heritage Fountain in downtown Olympia

Yelm City Park Splash Pad

Located at 115 Mosman Ave SE, the splash pad is open in the summer only

Splash pad at Yelm City Park
  • Briggs Community YMCA: Located in Olympia off of Yelm Highway, both lap swim and recreational swims are offered. 
  • Discover Aquatics
  • North Thurston High School Pool*
  • River Ridge High School Pool*
  • Timberline High School Pool*

*See City of Lacey Parks website for more information.

There are many wonderful locations to explore with a boat in Thurston County. Ensure to operate your vessel in accordance with the following knowledge.

Boating Safety

Thurston County has specific regulations regarding boating operations and water safety on lakes. Below are some key provisions from Title 16 – Waterways and Vessels.

  • Speeds over 5 mph are allowed only from 11 a.m. to 8 p.m. or official sunset, whichever comes first.
  • The maximum speed limit is 45 mph in the open basins.
  • After sunset, all crafts must use proper running lights.
  • Crafts operating over 5 mph must be at least 200 feet off the shoreline. This must be observed because swimmers and nonmotorized craft tend to gather within the 200-foot safety zone. This rule also reduces the impact of wakes upon shore banks. Thurston County has specific regulations regarding boating operations and water safety on lakes.
  • Crafts operating over 5 mph, including personal watercraft or "jet skis," must also remain at least 100 feet away from all other craft and persons.
  • All watercrafts must travel in a counterclockwise direction.
  • All water skiers must have at least three people: a driver, an observer, and a skier. The observer is required to watch the skier at all times and to use a red or orange flag to signal when a skier is down in the water. All water skiers are required to wear an approved flotation device.
  • Personal flotation devices must be on-board all watercraft, with one device required for each person and easily accessible. Children 12 years old and younger must wear a personal flotation device at all times if traveling on a vessel that is shorter than 19 feet.
  • You must be at least 16 years of age to operate a personal watercraft legally.
  • Must carry a Washington State Boater Education card.
  • All personal watercraft (or "jet ski") operators must wear an approved flotation device.
  • It is illegal to operate any craft while under the influence of drugs or alcohol.

Don't forget to check your boat for Eurasian Watermilfoil!  (Washington State Department of Ecology)

No Discharge Zone

The No Discharge Zone is a body of water where boats may not release sewage, whether treated or not. It helps protect public health, water quality, and sensitive resources. No discharge zone (Washington State Department of Ecology)

No Discharge Zone Picture

Water recreation program activities include facility inspection, education, manager certification training, poolside training, complaint investigation, and compliance enforcement. Read more about pool safety (WA DOH).

Thurston County Public Health and Social Services approves pool facility plans in conjunction with the Washington State Department of Health (WA DOH). WA DOH conducts pool plan reviews for new and existing facilities in Thurston County. Find information about plan submittal at the WA DOH website. Additionally, Thurston County requires operators to also complete the Water Recreation Facility Application.

Additional ​Resources

Contact the Water Quality at: 360-867-2626 or email us at if you have additional questions.