Water Quality

A small stream winds its way among dense green vegetation in a forest.

Water quality affects people's enjoyment of Point Reyes National Seashore's resources, and plays a direct role in the health of aquatic habitats. Water quality is a key indicator of the condition of aquatic resources and overall ecosystem health. Freshwater quality directly impacts marine water quality, human recreation and enjoyment, riparian habitat and wetland health, and nearly all aquatic and terrestrial species. It also affects the plants and animals that depend on these habitats, including threatened and endangered species like California freshwater shrimp, coho salmon, steelhead trout, and the California red-legged frog, which need high-quality freshwater.

In 2006, the National Park Service's Inventory and Monitoring Program began monitoring freshwater quality year-round under a long-term monitoring plan developed for the Golden Gate National Recreation Area, John Muir National Historic Site, Muir Woods National Monument, Pinnacles National Park, and Point Reyes National Seashore. Park staff measure basic parameters (such as temperature, pH, dissolved oxygen, and conductivity) on-site, collect water samples to measure turbidity, nutrients, and bacteria in the lab. Long-term water quality monitoring helps to document stream conditions, create a baseline dataset that can be used to look at changes over time, assess the effects of contamination or erosion, and provide direct feedback to guide management actions. In time, we will be able to analyze freshwater quality datasets in four of the network park units in order to determine range, variability, and trends. At present, we compare our observations with federal and state water quality objectives and publish these results on a biannual basis.

Marin County Environmental Health Services monitors a number of ocean, bay and freshwater sites within Point Reyes National Seashore and the surrounding area. These sites are sampled once a week from April 1 through October 31 to determine if a beach meets the California water quality standards for recreational water contact. EHS works cooperatively with the NPS to collect water samples and post advisory signage as needed at the designated sampling sites. For more information, visit the EHS's Marin County Ocean and Bay Water Quality Testing Program page or their Beach Water Quality Information page.

Learn more...

San Francisco Bay Area Inventory & Monitoring Network: Water Quality Monitoring

Loading results...

    Science & Research Project Summaries

    From 2006 to 2018, Point Reyes National Seashore and Pacific Coast Science and Learning Center (PCSLC) staff and communication interns assisted scientists conducting research through the PCSLC and the San Francisco Bay Area Inventory & Monitoring Network to produce a series of Resource Project Summaries, four of which were about water quality. These one- to two-page summaries provide information about the questions that the researchers hoped to answer, details about the project and methods, and the results of the research projects in a way that is easy to understand.

    Top of Page

    Last updated: February 4, 2024

    Park footer

    Contact Info

    Mailing Address:

    1 Bear Valley Road
    Point Reyes Station, CA 94956


    This number will initially be answered by an automated attendant, from which one can opt to access a name directory, listen to recorded information about the park (e.g., directions to the park; visitor center hours of operation; fire danger information; wildlife updates; ranger-led programs; seasonal events; etc.), or speak with a ranger. Please note that if you are calling between 4:30 pm and 10 am, park staff may not be available to answer your call.

    Contact Us