Backwater Valve

Sewer line valve that prevents sewage from flowing back into a home or business.

Biochemical Oxygen Demand (BOD)

A gross measure of wastewater strength. The regional plant uses an accelerated treatment process in which living bacteria, thriving in an oxygen-rich environment, consume material in the wastewater. Industry wastewater that is high in BOD requires more oxygen and is therefore more expensive to process.


Digested solids removed from wastewater.

Building Sewer

Small diameter sewer that connects a building or residence to the service sewer. The service sewer then connects the building sewer to the mainline. A cleanout is typically located at the connection between the building sewer and the service sewer.


A small sewer access hole through which equipment may be lowered for trouble-shooting or maintenance work.

Collection System

Sewer facility that collects sewage from private sewer services that has a capacity of less that one million gallons per day.


Small sewer pipes measuring twelve inches or less in diameter.

Commercial Sewer Customer

Any business that produces wastewater, except a business that falls under the definition of an industrial sewer customer.

Contributing Agencies

With respect to the organizational structure of the Sacramento Regional County Sanitation District (SRCSD), contributing agencies collect wastewater, while SRCSD conveys (transports) and treats wastewater. SRCSDs contributing agencies are the Sacramento Area Sewer District (SacSewer) and the cities of Sacramento and Folsom.

Cured-In-Place Pipe (CIPP)

Cured-in-place pipe (CIPP) is a liner that provides a seamless, corrosion-resistant, jointless "pipe-within-a-pipe." CIPP is installed through existing manholes and does not require extensive digging. After bypassing all sewer flow, the top of the manhole is temporarily removed. The CIPP liner is then pushed into the pipe from the manhole using water pressure. The liner is then cured to a hardened state using hot water or steam.

Double Wye

A service connection where a single lateral branches to serve two homes. These services cause problems when one house sits higher than the other and a stoppage occurs in the lateral, causing sewage from the higher house to flow into the lower house.


Also called utility easement, this is a portion of land, shared by a property owner and a public agency, that contains a public utility, such as a sewer pipe.


Treated, or partially treated, wastewater.


Equivalent single family dwellings.

Force Main

A force main pipe carries wastewater from a pump station to other pipes further along in the system. The word "force" refers to the fact that the pipe is under pressure, rather than relying on gravity to move wastewater.

Industrial Sewer Customer

Typically defined as any business that either discharges more than 25,000 gallons per day of wastewater to the sewer or is subject to certain U.S. Environmental Protection Agency regulations (examples include metal finishers or electroplaters)

Infill Development

Undeveloped areas within an urban area that is being provided sewer service.

Infiltration and Inflow (I/I)

Infiltration is water (typically groundwater) entering the sewer underground through cracks or openings in joints. Inflow is water (typically storm water or surface runoff) that enters the sewer from grates or unsealed manholes exposed to the surface.


Untreated wastewater - the wastewater that flows into a wastewater treatment plant.


Large sewer pipes, some as large as 10 feet in diameter, which form the backbone of a wastewater transport system.


General term that typically refers to either the building or service sewers. A lateral is a small diameter sewer that connects the building or residence to the mainline.

Main Line

Collector sewer pipes located in the street, or backyards, in the utility easement. Typically six to twelve inches in diameter, but can refer to larger diameter pipes as well.


A sewer access large enough for a person to enter to trouble-shoot sewer service problems or perform maintenance work.


Abbreviation for millions of gallons.


Abbreviation for millions of gallons per day.


A location where safe, treated wastewater is discharged into a river, ocean or other body of water. Also, the equipment and facilities at this location. The outfall for the Sacramento Regional Wastewater Treatment Plant is on the Sacramento River, near the town of Freeport.

Potable Water

Better known as drinking water.

Primary Treatment

A series of mechanical processes that remove solid material from wastewater. At the Sacramento Regional Wastewater Treatment Plant, primary treatment includes screening and settling processes.

Pump Station

Also known as "lift station." Sewer pipes are generally gravity driven. Wastewater typically flows slowly downhill until it reaches a certain low point. In areas where the geography does not allow gravity to propel sewage through the pipes, pump stations are necessary. They provide the necessary "lift" to get the sewage over a high point, and then gravity can once again take over the process. SacSewer owns, operates, and maintains 107 pump stations in its sewer system.

Recycled Water

Treated wastewater that undergoes additional, advanced treatment to make it safe for non-potable uses such as landscape irrigation.


The upgrading of older sewer systems, constructed in the 1950s or earlier, to present-day standards.


Permission from the property owner to enter the property beyond the easement. This is an important element of the project.

Secondary Treatment

Biological and mechanical processes that remove dissolved organic material from wastewater. At the Sacramento Regional Wastewater Treatment Plant, secondary treatment includes a biological process occurring inside oxygen reactor tanks and a settling process.

Smoke Testing

Procedure used to locate defects and unauthorized connections to the sanitary sewer system. Smoke is forced into the sewer, and then observed to see where it exits the sewer system. If a house is properly plumbed smoke will escape at the roof vent.

Storm Water

Consists of runoff from rain, irrigation and other urban and rural sources.


Overload; beyond capacity. If it is large enough, a surcharge will result in a sanitary sewer overflow.

Suspended Solids (SS)

The residue that is retained after filtering a sample of water or wastewater through a glass-fiber filter. The concentration of total suspended solids is the weight of the dried solids retained on the filter, divided by the volume of the sample from which the solids were collected.

Tertiary Treatment

An advanced level of wastewater treatment involving the removal of nutrients such as nitrogen and/or phosphorus from wastewater through biological or chemical treatment processes.


Sewer pipes measuring more than 12 inches in diameter and having a capacity of 1 to 10 million gallons per day. Trunk lines connect smaller sewer pipes, or collectors, to the largest transport pipes, or interceptors. The Central Trunk ranges from 33 to 60 inches in diameter and has a capacity that ranges from 10 to 45 million gallons per day.

Trunk Sheds

An area defined by a natural or artificial boundary that contributes sewage to a sewer facility which has a capacity of less than 10 million gallons per day.


Total Suspended Solids, a measure of the amount of solids in the wastewater. Wastewater is passed through a filter and the amount of material captured is measured relative to the amount of wastewater filtered.

Urban Service Boundary (Sacramento County's)

The area within Sacramento County that has been designated for Urban Sevices by a governing land use authority.


Also known as sewage, wastewater includes the water you flush down your toilet and the water that drains from your bathtub, sink, washing machine and many other domestic sources. Businesses and industries also produce wastewater.

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