Allegheny County Health Department

 
Combined Sewer Overflow Advisory

Frequently Asked Questions
About Combined Sewer Overflow (CSO) Alerts

What is a river water advisory?

A daily river water quality report issued during the recreational boating season, May 15 through September 30, to indicate whether a Combined Sewer Overflow (CSO) alert has been declared.

When is a CSO Alert Declared?

In wet weather, when combined sewer systems fill beyond their capacity to carry sewage and storm water, the excess flow is discharged, polluting rivers and streams. Look for marinas, docks and other sites along the rivers displaying an orange-colored flag with the black letters "C-S-O". This indicates an alert is in effect.

Does an alert prohibit river recreational activity?

No, but during an alert, people are cautioned to minimize water contact on river outings and to avoid contact with stream water. Anyone with a weakened immune system, open cuts or sores is especially vulnerable to infection from exposure to these contaminated waters.

Is tap water safe?

Water treatment plants are able to respond to changes in river water quality and still produce safe drinking water.

Are alerts canceled when it stops raining?

No. Once it stops raining, combined sewers continue to overflow until the excess sewage and storm water is drained out of the sewer system. An alert is usually canceled 24 to 36 hours after sewer overflows end.

How often are alerts declared?

Since River Water Advisories were introduced in 1995, 11 alerts on average, have been declared in duration from a single day to 45 days. An average alert lasts about seven days.

How can I find out when an alert is declared or canceled?

Please re-visit our website (www.achd.net) or call the Allegheny County Health Department's River Water Advisory hotline at 412-687-ACHD.

CSO Flag Sites
Allegheny RIver	Allegheny Marina; Brackenridge Water Plant; Brilliant Marina; Fox Chapel Marina; Millvale Marina; Oakmont Water Plant; Outboard Haven Marina; Pennsylvania Department of Environmental Protection Waterfront Offices; Pittsburgh River Rescue; Pittsburgh Water Plant; Tarentum Water Plant; Three Rivers Rowing Association; Upper Allegheny Valley Joint Sewage Plant; Washington’s Landing; and Locks & Dams #2, #3 and #4
Ohio River	Dashields Lock & Dam; Emsworth Lock & Dam; Groveton Boat Club; Midway Marina; River Quest; West View Water Plant.
Monongahela River	Carousel Marina; Clairton Sewage Plant; McKeesport Sewage Plant; Sandcastle; Locks & Dams #2 and #3
Youghiogheny River	Municipal Authority of Westmoreland County – McKeesport Water Plant