Building Backup
A wastewater or sewage release or backup into a building that is caused by blockages, flow conditions, or other malfunctions in the Collection System. A sewage backup or release is not a Building Backup if:

1. It is caused by blockages, flow conditions, or other malfunctions of a Private Lateral or other piping/conveyance system that is not owned or operationally controlled by Baltimore; or
2. It is the result of overland, surface flooding not emanating from the Collection System.

Clean Water Act (CWA)
A federal law enacted by Congress to regulate discharges of pollution into waters of the United States from point sources (e.g., pipes, manholes, etc.)

Dry Weather Overflow
A sanitary sewer overflow that is unrelated to precipitation related flows (including storm water and snow melt runoff). Per the terms of the consent decree, it is presumed that flow in the Collection System more than 72 hours after a rain event or snow melt event is unrelated to rain or snow melt.

Department of Justice (DOJ)
An agency of the United States government headed by the Attorney General that represents the United States before the federal courts. The United States Attorney General is the head of DOJ.

Environmental Protection Agency (EPA)
An agency of the United States government that is charged with enforcing various federal environmental laws, including the Clean Water Act.

Infiltration
The water entering the Collection System from the ground through means that include, but are not limited to, defective pipes and sewer walls, pipe and sewer joints, connections, and manhole walls as defined by 40 C.F.R. § 35.2005(b)(20).

Inflow
Water, other than wastewater, that enters the Collection System (including sewer service connections) from sources such as, but not limited to, roof leaders, cellar drains, basement sump pumps, area drains in yards and driveways, foundation drains, cooling water discharges, drains from springs and swampy areas, cracked or broken manhole covers, cross connections from separate storm sewers, catch basins, cooling towers, storm water, surface run-off, street wash waters or drainage as defined by 40 C.F.R. § 35.2005(b)(21).

Level of Protection (LOP)
The measures necessary to limit the occurrence of SSO’s to once every 5 or 10 years, respectively.

Maryland Department of the Environment (MDE)
An agency of the State of Maryland that is charged with enforcing various State and federal environmental laws, including the Clean Water Act.

Sanitary Discharge of Unknown Origin (SDUO)
Any discharge of sewage through Baltimore’s separate storm sewer system, where the source of the sewage is unknown.  Once the source of the SDUO is confirmed, if it originates from the Collection System, it is then a Sanitary Sewer Overflow.

Sanitary Sewer Overflow (SSO)
An un-permitted discharge of sewage into waters of the United States from a point source (e.g., pipe, manhole, etc.) The City pays civil penalties to the State of Maryland and the federal government for each SSO that occurs in violation of the Clean Water Act.

Sanitary Sewer System
The system of pipes, pump stations, manholes, etc., that is designed to convey sewage from homes and businesses to a wastewater treatment plant for treatment. The sanitary sewer system is not designed to convey un-contaminated stormwater or groundwater.

Sensitive Areas
Outstanding National Resource Waters, National Marine Sanctuaries, waters with threatened or endangered species and their habitat, waters where primary contact recreation is common, public drinking water intakes or their designated protection areas, shellfish beds, and areas within one hundred (100) feet from a public recreation area, a school, a day care center, a hospital or a similar establishment with potentially sensitive populations.

Structured Overflow
An engineered relief point that discharges sewage into the environment during wet weather in order to relieve pressure within the system. Overflow structures were created prior to the inception of the Clean Water Act and the EPA.