The City of Elgin & The Fox River

The City of Elgin began serving its residents as a community water supplier in the late 1880s. At that time, the Fox River was used as the source of drinking water. The fact that no treatment was performed on the raw water leads one to speculate that at that time the Fox River must have been a pristine source.

The Water Department facilities were located on the east bank of the Fox River at what is now the Slade Avenue Pumping Station. The facilities then consisted of a small pump building. The water was pumped from the river directly to the customer's home via water mains made from wood planks. This system carried Elgin into the 20th century.

In 1900, waterborne diseases became prevalent in the Fox River, likely due to the fact that the once virgin river was being used more and more. The surrounding area was growing, and most communities along the river used the Fox not only as a source of drinking water but also for recreation and industry. This contributed to the downfall of its water quality and the city decided to find an alternate source of raw water. The next logical choice was groundwater.

The City of Elgin Deep Wells

In 1901, the city drilled its first deep well at the Slade Avenue site. During the next couple of years, the city had three more deep wells drilled to a depth of 2,000 feet, tapping into the Cambrian-Ordovician Aquifer. An aquifer is a supply of water far below the surface of the earth and is a result of water seeping through dirt, sand, and rock. In effect, the water filtering through the earth is cleansed and collects below. The Cambrian-Ordovician Aquifer lies under much of northern Illinois.

Fox River Treatment Facilities

In 1936, the city built a treatment facility at the Slade Avenue site to treat the well water. This facility consisted of settling basins, chemical feed systems, and sand filters. By 1940, the city was producing an average of 2.29 million gallons a day of well water. This was the city's only source of treated water until 1963, when the Airlite Street Water Treatment Plant was built to service the quickly expanding west side.

By 1965 the city was providing an average of 5.46 million gallons of water a day. As Elgin grew, so did its demand for natural resources, such as water. A growing number of communities were sprouting up in northern Illinois and drilling into the Cambrian-Ordovician Aquifer. This put a strain on the aquifer, similar to many people sticking a straw into a giant glass of water and trying to take a sip at the same time.

In 1970 Elgin was taking an average 7 million gallons of water a day from this aquifer. It was time to plan for the future, as the aquifer's level was dropping at an alarming rate. As the water table dropped, the more it cost in electricity to pump the water to the surface.

Searching for Alternative Sources of Water

In the mid 1970s, Elgin began exploring for alternate sources of raw water. Officials even considered buying water from the City of Chicago, which uses Lake Michigan as its raw source. The city decided it did not want to depend upon someone else for such a precious commodity, especially since there was an excellent raw source right in its backyard, the Fox River.

By now the river had gone full circle and was on the upswing in terms of water quality. This change can be traced to the 1960s when ecological awareness was brought to the forefront. It was decided in 1979 to build a new treatment facility that could process Fox River water at a rate of 16 million gallons a day.

The Riverside Treatment Facility

In 1982 the Riverside Treatment Facility was completed on the west bank of the Fox River directly across from the Slade Avenue Treatment facility. The city now had an asset that many communities only dreamed of: a virtually unlimited reliable source of raw water. The decision to return to the Fox River as a water source has continued to help Elgin attract large corporations and developments, many of which would not locate here without an ample water supply.

When the new facility began service, the Slade Avenue plant ceased treating water, but the facility was maintained until 1990 for its water storage and pumping capabilities. In 1990 the old Slade Avenue Treatment Facility was razed, and a new facility was built in its place. This facility houses the Water Department's meter division and still serves as a pumping station.

On April 29, 1997, the Water Department broke ground on its $17.5 million expansion of the Riverside Water Treatment Plant. This expansion doubled the plant's capacity to 32 million gallons of water a day.


Approximately 94% of Elgin's raw water is from the Fox River with the remaining 6% drawn from deep wells. The water is treated and tested per the Environmental Protection Agency regulations. The raw water undergoes a tertiary treatment process, including coagulation / sedimentation, lime softening, chlorination, and filtration.

Raw Water Facts

The raw river water has a hardness of 260 to 400 milligrams per liter (15 to 24 grains per gallon) and is softened to 135 mg/L (7.9 grains per gallon). There is a total combined chlorine residual of 3.0 mg/L for disinfection. Fluoride is mandated and added for the prevention of tooth decay.