Granite St. Swimming Reservoir, Lithia Park, Ashland is sampled weekly from June 15th from October 1st.

Water samples are collected by Rogue Riverkeeper volunteers and our Water Quality intern processes and tests the samples in our lab which meets the OR Dept. of Environmental Quality data standards. Results are then posted to this page so you will know when it is safe (or unsafe) to swim!

Oregon state criteria for whether a water sample meets the water quality standard for contact is an E. coli result of 406 MPN/100mL per sample or less. Water samples are collected, then sealed and incubated over a 24-hour period at 35+/- degrees Celsius. The results are considered valid for 7 days.Results based on the Oregon water quality criteria of 406 MPN/100mL are organized as follows:GREEN = a single sample is below the Oregon water quality criteria for water contactYELLOW = a single sample is at Oregon water quality criteria, nearing unsafe water contact. Caution should be taken when recreating in sites marked yellow. RED = a single sample exceeds the Oregon water quality criteria.. People and pets should not be recreating in sites labeled red as bacteria levels are considered unsafe for human contact. GREY = a site with no current data available. SPECIAL STATUS = a toxic algae bloom was observed. Some species of blue-green algae can be toxic and may cause illness in people, pets and other animals if accidentally consumed.Always use your best judgement when recreating in or near waterways. Pay attention to odd smells, colors, water quality, etc and report anything that looks out of the ordinary.Be safe, have fun, and thank you for protecting the Rogue!