Ejector Pump Requirements in Chicago

Ejector pumps serve a critical drainage function in Chicago buildings where plumbing fixtures are installed below the level of the municipal sewer main — a common condition in the city's older housing stock and basement-heavy residential architecture. Chicago's regulatory framework, administered through the Chicago Department of Buildings and governed by the Chicago Plumbing Code, imposes specific equipment, permitting, and installation standards on ejector systems. Understanding how these requirements are structured helps property owners, licensed plumbers, and building inspectors navigate compliance obligations across residential and commercial contexts. The full regulatory context for Chicago plumbing shapes how these standards are applied and enforced.

Definition and scope

An ejector pump — also called a sewage ejector pump — is a submersible electromechanical device installed in a sealed basin (pit) that collects wastewater from below-grade fixtures and forces that waste upward through a discharge pipe into the building's main drain line, which then flows by gravity into the municipal sewer system.

The Chicago Plumbing Code, which adopts and modifies the Illinois State Plumbing Code (225 ILCS 320), draws a classification distinction between two primary pump types:

1. Sewage ejector pumps — handle blackwater (toilet waste) and greywater from below-grade fixtures including toilets, sinks, laundry tubs, and floor drains. These require a sealed, airtight basin with a vented cover.
2. Sump pumps — designed exclusively for groundwater and stormwater drainage. Sump pumps are prohibited from receiving sanitary waste under Chicago plumbing code provisions and under the Illinois Environmental Protection Act (415 ILCS 5).

These two systems are sometimes confused in field settings, but connecting sanitary waste to a sump system constitutes a code violation subject to enforcement by the Chicago Department of Buildings.

Scope coverage: This page addresses ejector pump requirements as they apply within the City of Chicago's municipal jurisdiction. Requirements for suburban Cook County municipalities, DuPage County, or other collar counties fall outside this scope, as those jurisdictions may follow different local amendments to the Illinois Plumbing Code. Commercial high-rise applications involve additional provisions covered separately under Chicago's high-rise plumbing standards.

How it works

A standard sewage ejector system consists of four primary components: the collection basin (minimum 18-inch diameter in most residential applications), the submersible pump motor, a check valve on the discharge line, and a vent pipe connected to the building's drainage vent stack.

The operational cycle follows this sequence:

1. Wastewater from below-grade fixtures drains by gravity into the sealed basin.
2. A float switch activates the pump motor when wastewater reaches a preset level — typically 12 to 18 inches of accumulation.
3. The pump impeller shreds solids and forces the slurry upward through a 2-inch minimum discharge pipe (3-inch is standard for systems serving a toilet).
4. A spring-loaded check valve prevents backflow when the pump deactivates.
5. Wastewater enters the building's main drain at or above the sewer invert level and continues to the Chicago sewer system by gravity.

Basin covers must be gastight and sealed to prevent sewer gas — primarily methane and hydrogen sulfide — from entering occupied spaces. The vent connection is non-optional under both the Chicago Plumbing Code and OSHA's confined space and air quality standards (29 CFR 1910.146).

Pump capacity is sized by calculating fixture unit load (per Illinois Plumbing Code Table values) and accounting for the total dynamic head — the vertical lift distance plus pipe friction losses. A residential system serving one bathroom typically requires a pump rated between 4/10 and 1/2 horsepower, capable of delivering 20 to 40 gallons per minute against the required head.

Common scenarios

Ejector pump installations arise in predictable Chicago building contexts:

Basement bathrooms in two-flats and three-flats. Chicago's dense stock of two-flat and three-flat buildings — many constructed between 1890 and 1940 — frequently feature basement units or finished basement spaces where the floor drain and toilet rough-in sit below the street sewer elevation. Plumbing considerations for two-flat and three-flat buildings frequently center on this condition.

Coach house and garden unit conversions. When a coach house or basement is converted to a dwelling unit, any new sanitary fixtures below sewer grade require a permitted ejector installation before occupancy approval.

Basement laundry additions. Adding a washing machine standpipe, laundry tub, or utility sink in a basement that drains below sewer invert requires ejector service rather than a direct drain connection.

Commercial basement buildouts. Restaurants, retail spaces, and offices occupying basement levels of Chicago commercial buildings must provide ejector service for any restroom or kitchen drain below the sewer invert, subject to Chicago commercial plumbing requirements.

Flooding-related remediation. Properties installing interior drain tile systems as part of basement flooding and backflow prevention work sometimes require ejector upgrades to handle redirected interior drainage.

Decision boundaries

Several threshold conditions determine whether an ejector pump is required, what specifications apply, and what permit pathway is triggered.

Is the fixture below sewer grade? This is the threshold question. A licensed plumber determines sewer invert elevation by referencing the City of Chicago's sewer atlas records (available through the Department of Water Management) and measuring the proposed fixture rough-in elevation. If the fixture drain is at or above sewer invert, gravity drainage is permitted. If below, ejector service is mandatory.

Does the system receive toilet waste? If yes, the basin must be sealed/airtight and the discharge pipe must be a minimum 3-inch diameter under Illinois Plumbing Code standards. Systems serving only greywater (sinks, laundry, floor drains) may use 2-inch discharge in some configurations, but basin sealing is still required for sanitary connections.

Permitting requirements. Any new ejector pump installation in Chicago requires a plumbing permit issued by the Chicago Department of Buildings. Permit applications must be filed by a licensed plumber in Chicago holding a valid City of Chicago plumbing license. Rough-in inspection and final inspection are both required before the system is placed in service. Replacing an existing ejector pump with an identical unit in the same basin location may qualify as a like-for-like replacement with a simpler permit pathway, but any relocation or basin modification triggers full permit requirements.

Alarm and redundancy requirements. The Chicago Plumbing Code requires a high-water alarm on ejector basins serving residential dwelling units. Commercial applications above a certain fixture unit threshold may require duplex (redundant) pump configurations — two pumps installed in a single basin with alternating operation, ensuring service continuity if one unit fails.

The Chicago plumbing authority index provides additional orientation to how these requirements connect to the broader regulatory and inspection landscape governing plumbing in the city.

References

• Illinois Compiled Statutes — Illinois Plumbing License Law, 225 ILCS 320
• Illinois Compiled Statutes — Illinois Environmental Protection Act, 415 ILCS 5
• Chicago Department of Buildings — Permit and Inspection Services
• City of Chicago Department of Water Management
• OSHA Standard 29 CFR 1910.146 — Permit-Required Confined Spaces
• Illinois Plumbing Code — Illinois Department of Public Health