1. Operational Response to an E. coli Event and Lessons Learned City of Mercer Island September 27 – October 8, 2014 Dave Muto Manager of Water System Operations

2. Source of Supply to Mercer Island Mercer Island is a SPU wholesale customer – Purchases all water – One well for emergency use, must boil before drinking Pipeline from Factoria area along I 90 – Feed can be Tolt or Cedar water or a blend Three service connections with SPU 2

3. Distribution System Five major pressure zones 30+ small PRV fed zones along shoreline Two pump stations Two 4 MG tanks 121 miles of water mains – primarily unlined cast iron 7,500 service connections – ~ 22,000 residents Five sample stands – 18 TCR samples required per month 3

4. Timeline of Events Saturday 9/27, 1515 hrs. Boil water advisory issued – All food service operations suspended (62 locations) Monday 9/29, 0845 hrs. Boil water advisory lifted – MI School District closed to sanitize facilities – SKCPH inspections of restaurants required prior to reopening Thursday 10/2, 1245 hrs. Second boil water advisory issued – No precedent for back to back events – School District elected to stay open Wednesday 10/8, 1200 hrs. Boil water advisory lifted – Development of criteria for lifting boil order

5. Impacts to the Public Food service – Food prep, ice, soda and coffee machines – Produce misting systems – Seafood and meat Schools closed – Child care issues – Day care/pre-school Vulnerable populations – Elder, youth, immuno-compromised Medical / dental facilities – Home facilities Economic impacts haven’t been fully determined

6. Challenges of Public Notification Ten required elements in a public notice for acute violations – What happened – When did it happen – What’s being done about it – What should I do – Where can I get more info How do you deliver the message – Press conference/press release – TV, radio, print media – Reverse 911 – Phone banks – Posters and flyers – Door to door – Website and social media

7. Boil Water Advisory Event - #14-3872 Notification and Media FIRST ACTIONS Backbone = “Reverse- 911” type system Press release Full press conference Interviews: live TV, radio, and phone Postering Public Health closures Vulnerable pops. Challenges & Considerations  Not completed, poor performance  Multi-author! Contact info  Ensure space available/EOC  Who’s available & do they have talking points? Elected  Who, where, waterproof?  Staffing, media intrusion  Updated lists? Calls/visits A “silent incident” with urgent outbound communication needs

8. Boil Water Advisory Event - #14-3872 Notification and Media FIRST ACTIONS Social Media City Website Email lists Notifying City Challenges & Considerations  Early & often; photos!; care & feeding; replies; NextDoor.com  Quick updates difficult; timestamp; missed deadlines  Many places, many formats; be creative (e.g. utility billing)  All-staff emails; text alerts; City Council

9. Boil Water Advisory Event - #14-3872 Notification and Media MID-INCIDENT Notification Improvements Phone bank messages Request info from public Challenges & Considerations  Reader boards; DOT sign; larger posters; A-frames  Ensure simple & timely; public health info  Encourage people to engage (revealing backflow issues)

10. Boil Water Advisory Event - #14-3872 Notification and Media LATE-INCIDENT Prepare FAQ’s, and “What to do when” Plan for proactive good news stories (vols, staff) Recovery plan, public reassurance Plan for questions about legal and $$ Challenges & Considerations  Tough to assemble all needed guidance  Find most interested media contacts  Dine Local Campaign promo; Loans; Restaurant map  City Attorney

11. Mutual Aid from Other Utilities City of Bellevue – Assist with flushing City of Issaquah – Assist with flushing SPU Water Quality Engineers – Technical advice SPU WQ Lab Staff – Sample collection and processing SPU Water Treatment – Booster chlorination

12. Assistance with Booster Chlorination DOH wanted to see higher residuals throughout system – MI did not have capability to perform this work SPU assistance requested – SPU had equipment, supplies and staff expertise – Unsure of what we had to work with on site Boosting began Thurs. October 2 nd —Continued 10/3, 10/6, 10/7, 10/9, and 10/14 —Calcium hypochlorite tabs also used in reservoir by MI staff

16. Booster Pump System Schematic

17. Criteria for Lifting Boil Advisory Five milestones established – Six consecutive days of clear samples – Completion of an Investigative Action Plan – Maintained boosted chlorine residual in the reservoirs – Demonstrated and monitored elevated chlorine residuals in distribution system – Development of post-rain event inspection protocol for high-risk underground vaults Continued extra sampling and chlorine boosting after boil advisory lifted

18. Economic Impact to the Utility Staff overtime Bottled water for customers Diver inspection of reservoirs Additional lab tests Equipment rentals Printing Food for staff and volunteers Lost revenue Backlog of work deferred during event New capital improvements