Environmental Health Services
9100 Franklin Square Drive, Suite 230
Baltimore, Maryland 21237-3903
Phone: 410-887-FOOD (3663)
TTY users call via Maryland Relay
Baltimore County has almost 200 miles of tidal coastline as well as public and privately owned and operated tidal and fresh water recreational bathing beaches. In addition, the availability of these recreational water resources supports a significant number of related activities such as commercial and recreational fishing, skiing, camping and boating. Environmental Health Services (EHS) conducts recreational water sampling, provides water sampling in support of sewer overflow investigations and regulates bathing beaches and public swimming pools for the health and safety of the public.
View what precautions to take (PDF flyer) when water sample results fail to meet federal and state standards.
Recreational Water Quality
Environmental Health Services (EHS) routinely conducts bacteriological sampling of many areas in an effort to provide information to the public on water quality and promote the safe use of these resources. View a map of the associated water sampling areas and locations (PDF - File is 2.4MB and may take several minutes to download).
This sampling utilizes the bacteriological indicator organism Enterococci for salt water and Escherichia coli (E. coli) for fresh water. These organisms are found in the intestines of all warm-blooded animals and are important chiefly because, when found in higher concentrations in conjunction with a known or suspected source of sewage contamination, the probable presence of other more pathogenic organisms is indicated.
A history of sampling helps to provide some of the background information needed to evaluate long-term trends in water quality. Water conditions change constantly. It should be noted that any single sample or group of samples represents a “snap shot in time” and should not be used without other supporting information to characterize the water quality of a particular river, lake or bay.
Water users should remember that all natural waters support many different microorganisms. Some of these organisms are pathogenic to humans; however, most are not. Water users should note that murky or debris-strewn water, which often occurs after violent storms or heavy rains, is a general indication of poor water quality. Excessive storm water runoff after heavy rains can carry pet waste, agricultural waste or fecal contaminants from brief sewage overflows as well as various chemicals including those associated with commercial and residential lawn care.
Swimmers, skiers, boaters or any one whose activities will bring them into close contact with natural waters should always take into consideration their own observations before entering the water. Natural waters should never be considered safe for ingestion.
Water Contact Alert
Should sampling by the County measure elevated bacteriological levels due to a known or suspected sewage overflow, that would make water activities unsafe or unhealthy at a particular location, a water contact alert will be issued. In the event that these conditions affect a public bathing beach, that beach will be closed. The Water Contact Alert will be posted and a press release will be issued to major media outlets. Signage may also be posted at points of greatest access to the affected body of water.
In open waters, the public will be advised to minimize water contact and the health risks associated with sewage contaminated waters will be explained. After a water contact alert has been issued, the conditions, which may have contributed to poor water quality, will be investigated. After those conditions have abated, sampling will resume to determine when the water quality has improved to an acceptable level. The water contact alert will then be lifted.
Water Quality Advisories
When monitoring in open areas of water indicates a widespread, abnormal rise in the concentration of bacteria and there is no known or suspected sewer overflow, a Water Quality Advisory may be issued. These conditions are typically associated with storm water runoff. Water Quality Advisories are non-regulatory and usually temporary in nature. Advisories are issued to provide recommended precautions for recreational water users and applicable public health recommendations will be noted on this web site. Precautionary signage is not typically posted for Water Quality Advisories, however a press release may be issued if conditions are widespread and severe.
Water Quality Signage
In an effort to inform the public regarding specific health related precautions, various types of signage may be found in and around access points to both fresh and tidal waters.
Stream Sense (PDF)
Revised September 29, 2016