To help communicate with the public about local water quality, MSD maintains a CSO Notification Program which includes signage, notification emails, and a CSO Activity Map.
A CSO is a combined sewer overflow. Much of Hamilton County is served by combined sewers, which carry both wastewater from homes and businesses and stormwater runoff from roads, buildings, and the ground. During heavy rains, combined sewers can fill up with too much stormwater and overflow into local rivers and streams. MSD has invested billions of dollars to significantly reduce the overflows, but work continues to address this problem. LEARN ABOUT MSD'S WET WEATHER PROGRAM.
The public should avoid contact with impacted streams or rivers for at least 72 hours after a rainfall or after water levels have returned to normal. This includes refraining from participating in activities such as boating, wading, fishing and swimming.
The public should always exercise caution when in and around local waterways, as conditions can change quickly! Do not rely solely on signs, emails, or the CSO Activity Map to keep yourself, your family, and your pets safe.
To alert the public to the potential for CSOs, signs are posted at each CSO discharge location along the Ohio River, Mill Creek, Little Miami River, Muddy Creek and their tributaries.
You can receive CSO Advisories by email by subscribing to the CSO Public Notification mailing list. Subscriptions are free and are easy to setup, just click the Sign Up Now button below and enter in your name and email:
Any CSO that is suspected to be actively discharging or is suspected to have discharged in the last 72 hours is shown on the map. Please remember to refresh your browser frequently to see the most up-to-date information.
NOTE: MSD maintains an advanced system of sensors that monitor the conditions at all CSO outfalls. Data is available within 15 minutes of its measurement so while the CSO Activity Map isn’t a “live” video feed, it shows the conditions in near real-time. While the system is highly reliable, there still can be false alerts. MSD reviews this data daily and reports all confirmed overflows to the Ohio EPA within 24 hours.