The Environmental Health Department of the Nevada County Community Development Agency is responsible for programs focused on environmental protection and public health in Nevada County. These programs regulate food preparation in restaurants, installation of wells and septic systems, handling hazardous materials and other topics related to consumer protection. https://www.nevadacountyca.gov/1470/Environmental-Health

From time to time there are giveaways of mosquito fish. Mosquito fish can consume large quantities of insect larvae in your pond or other standing bodies of water. By reducing the mosquito population, you can reduce your risk of contracting mosquito-borne diseases including the West Nile Virus. These fish are not native, they are invasive species. These fish are only meant for closed/stagnant ponds. They should not be placed into ponds that can drain into the local creeks and streams. This can have negative impacts on the native ecosystem. If your pond has outlets, please do not acquire these fish.
2022 mosquito fish giveaways are in May and June. Info here: https://www.nevadacountyca.gov/2291/West-Nile-Virus-Mosquito-Prevention