333-061-0540 Cyanotoxin Monitoring (1) Water suppliers with raw water intakes into susceptible sources must monitor as follows: (a) At raw water sampling points: (A) From May 1 through October 31, water suppliers must monitor at the raw water sampling point at least once every two weeks for cyanotoxins. Samples from upstream locations collected for recreational or other purposes may be substituted for raw water sampling if approved by the Oregon Health Authority (Authority) based on proximity and characteristics of sampling locations, sampling techniques and analytical methods used, and intake construction. (B) If at any time total microcystins are detected at greater than or equal to 0.20 µg/L or cylindrospermopsin is detected at greater than or equal to 0.30 µg/L in raw water, or there is a recreational use health advisory in a water body upstream, water suppliers must immediately increase raw water monitoring of cyanotoxins to weekly. (C) Water suppliers may resume raw water monitoring every two weeks if there is not a recreational use health advisory upstream and total microcystins are not detected or are detected at less than 0.20 µg/L and cylindrospermopsin is not detected or is detected at less than 0.30 µg/L in at least two consecutive weekly samples. (b) At entry points: (A) If total microcystins are detected at greater than or equal to 0.20 µg/L or cylindrospermopsin is detected at greater than or equal to 0.30 µg/L at the raw water sampling point, water suppliers must monitor for cyanotoxins at the entry point weekly, beginning within one business day of receiving raw water results. (B) If cyanotoxins are detected at any entry point sample, water suppliers must immediately take steps to optimize existing facilities or treatment processes to reduce cyanotoxins and begin monitoring at the entry point daily beginning within 24 hours of notification of results. (C) Water suppliers may resume weekly entry point monitoring if cyanotoxins are not detected in two consecutive daily samples collected at the entry point. (D) Water suppliers may cease entry point monitoring if total microcystins are not detected or are detected at less than 0.20 µg/L and cylindrospermopsin is not detected or detected at less than 0.30 µg/L in two consecutive samples of the raw water and is not detected in two consecutive entry point or distribution samples. (2) Monitoring following a cyanotoxin health advisory level exceedance at entry point. (a) If the cyanotoxin concentration exceeds a health advisory level in a sample collected at the entry point, the water supplier must collect a confirmation sample from the entry point as soon as practical, but no later than 24 hours after receiving results. (b) At water systems where a health advisory is in effect, water suppliers must sample in the distribution system according to OAR 333-061-0570(4) in order for the health advisory to be lifted. Additional distribution system monitoring may be required by the Authority based on sampling results and other relevant circumstances. Distribution monitoring may cease when the advisory is lifted. (c) Once the health advisory is lifted as permitted under OAR 333-061-0570(4), water suppliers must monitor no less frequently than prescribed in section (1) of this rule. (3) The Authority may extend the monitoring timeline required pursuant to this rule on a case-by-case basis upon a request from a water supplier, when the water supplier has a logistical problem timely collecting or analyzing samples in accordance with the requirements of OAR 333-061-0510 to 333-061-0580. When an extension is approved by the Authority, the Authority must specify in writing how much time the water supplier has to monitor. Examples of logistical problems could include, but are not limited to: (a) Extreme weather conditions that create unsafe travel or on-site conditions for the person collecting the sample. (b) Limited laboratory capacity on weekends and holidays. Statutory/Other Authority: ORS 448.123, 448.131 & 448.150 Statutes/Other Implemented: ORS 448.123 & 448.150 History: PH 118-2024, amend filed 12/13/2024, effective 01/01/2025 PH 7-2023, amend filed 01/31/2023, effective 02/01/2023 PH 284-2018, adopt filed 12/21/2018, effective 12/21/2018 PH 231-2018, temporary adopt filed 06/26/2018, effective 07/01/2018 through 12/27/2018