Half of all the electricity consumed at one of the largest wastewater treatment facilities in the Midwest goes to running air blowers and pumps. That was the detail that stuck with me most from Saturday’s open house at the Terrence J. O’Brien Water Reclamation Plant at the corner of Howard Street and McCormick Boulevard in Skokie, one of seven facilities operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRD).
I visited with two friends; I think we left there with a clearer picture of the hidden machinery behind our region’s daily life.
Upon arriving one hears a loud and consistent noise. This turns out to be air moving through these large pipes from the blower and pump room to the aeration tanks.
A plant almost a century old
The O’Brien plant opened in October 1928. At the time, it was the largest sewage treatment facility in the world. Nearly a century later, it still serves over 1.3 million people across 143 square miles: Chicago north of Fullerton Avenue and 17 north suburban Cook County communities including Evanston, Skokie, Wilmette, Northbrook, and Glenview. Wastewater from all of those homes and businesses travels through a network of intercepting sewers beneath McCormick Boulevard before arriving at the plant’s 97-acre campus at Howard Street.
The MWRD service area map shows the locations of the seven water treatment plants (Hanover Park, Egan, Kirie, O’Brien, Stickney, Lemont, and Calumet) using a green icon. Download as PDF.
The plant was renamed for Terrence J. O’Brien, a longtime MWRD president who died in 2021. It’s one of seven plants in the district, each serving a distinct drainage area across the Chicago region.
Simpler than you’d think — and more remarkable for it
The treatment process is more straightforward than most people imagine. Incoming wastewater first passes through screens that remove large debris, then into settling tanks where solids drop out — capturing 60 to 80 percent of suspended material. After that, the water moves into aeration tanks where staff introduce what they affectionately call “bugs”: beneficial bacteria that consume the remaining organic matter. A final round of ultraviolet light disinfection kills any remaining pathogens before the treated water discharges into the North Shore Channel. This effluent is cleaner than the water in the channel.
That channel, built between 1907 and 1910, carries the plant’s effluent south toward the Chicago River — an engineered system designed to move water away from the lake and through the region. Because much of Chicago relies on combined sewers — single pipes carrying both stormwater and sewage — heavy rain events send a surge of combined flow toward the plant. It connects to TARP, the Deep Tunnel system, which captures and holds that overflow until the plant can process it. The plant handles an average of 230 million gallons per day, with surge capacity up to 450 million. At the time of our visit the plant had processed 156 million gallons.
The pump and blower room has pumps that push the water up to the first tanks, after which gravity moves the water from stage to stage. The blowers push air into the tanks so that dissolve oxygen facilitates the growth of beneficial bacteria. Left: pumps, and a small sign that counts the number of gallons pumped today. Right: a blower machine.
Touring the plant
The MWRD ran an efficient open house, with guided tours departing every 15 minutes. Our guide was a retired staffer who came back to volunteer. Before working there for 10 years he worked at a suburban municipality’s drinking water plant.
A highlight was the 1926 Pump and Blower Building, a vaulted brick-and-steel industrial hall with a skylit roof that. Inside, massive blowers push air into the aeration tanks to keep the bacteria alive and working. Those machines account for roughly half the facility’s entire electricity consumption. It’s a staggering thought: hundreds of millions of gallons treated daily, and the biggest energy draw is simply moving some air.
We weren’t allowed into the grit chamber during the open house, but our guide noted that school groups regularly visit it — and that children almost universally react to the smell by pulling their shirts over their noses.
Infrastructure worth knowing
More people should understand how the infrastructure they pay for and benefit from actually works. The O’Brien open house is a rare chance to do exactly that: to stand next to the blowers, walk past the settling tanks, and talk to the people who run it. Staff talked to us about how they test at the plant and at businesses that generate “industrial wastewater”, including breweries and metal processing facilities.
Left: primary treatment tank, where sand and gravel fall to the bottom and fats and plastic float to the top; both are skimmed and removed. Center and right: the tour guide describes the secondary treatment process in which “bugs” (beneficial bacteria) have a feast on the remaining organic matter.
The staff also test for viruses as well as fecal matter to assess the effluent’s cleanliness. The tour guide said that before the water enters the UV channels Before the UV channels the water has over 1,000 fecal coliform per 100 mL; after treatment it drops to 25, sometimes as low as 3. The MWRD’s NPDES permit sets the effluent limit at 200/100 mL as a 30-day geometric mean, so readings of 3–25 represent the plant performing well above the requirement.
The process is elegant in its logic, the history is genuinely impressive, and the scale is humbling. MWRD’s website does a better job than I at summarizing the process. The MWRD holds open houses at several of its water treatment plants each year. There are two more this month:
Earlier this month I made the trip down to Springfield to volunteer with Abundant Housing Illinois, an advocacy organization pushing for more housing options across the state. It was our biggest group ever, with 39 people going from five Illinois municipalities, and most of us took Amtrak there and back.
The day was a mix of orientation, refining our housing stories and why we volunteer, and then walking the halls of the Capitol to speak with legislators and their staff. Our housing advocates talked to twenty Illinois General Assembly members about reforming local codes that prevent people from being able to afford housing all over the state. We spoke in support of the BUILD plan I wrote about earlier.
Chloe, Rep. Bob Morgan, BenEveryone wore their AHIL t-shirtGov. Pritzker happened to come down the stairs near our groupPhotos by Stephen Stassen
It’s important – although inefficient – to show up in person and make the case directly. The legislators we met with were highly or quite receptive, though you never quite know what interactions or talking points will actually move the needle. All of the six bills in the BUILD plan have not yet passed committee; but that doesn’t stop them from moving forward through other means.
If you care about housing in Illinois — whether that’s affordability, supply, or just the ability to build an ADU in your backyard — Abundant Housing Illinois is worth knowing about. Join us!
The Chicago Crashes page that is hosted on Chicago Cityscape shows weekly and year-to-date crash statistics along with estimated costs of those crashes, broken down by person type. Today I published a major change to present the stats better, in a way that matches the costs of the crash that are said to be different based on the person’s situation – whether they were a pedestrian, bicyclists, or motor vehicle occupant – in the crash. Prior to this change, every person in the crash was assigned the same monetary cost as “driver” even if they were a pedestrian or bicyclist.
Improved cost tables
The “Costs of these crashes” tables have two improvements.
Each injury-severity column now shows a count alongside the dollar figure, so you can see exactly how many people of each type were killed, had incapacitating injuries, or had non-incapacitating injuries for the selected time period. This makes it easier to verify the numbers and understand the scale behind the cost estimates.
The tables previously listed three person-type rows: Driver/Passenger, Pedestrian, and Bicycle. The CPD dataset actually includes six person types. The two remaining types — non-motor vehicle occupants and non-contact vehicle occupants — were being silently folded into the Driver/Passenger row. They now appear in their own “Other” row.
What’s interesting is the differences in value. Pedestrian is “worth” less than bicyclist. Cost estimates use values from the CDC’s WISQARS Cost of Injury study and vary by injury severity and person type.
A pedestrian who is killed is said to result in $14,169 in medical costs and $10,500,000 in non-medical costs, totaling $10,514,169
A bicyclist who is killed is said to result in $19,750 in medical costs and $10,800,000 in non-medical costs, totaling $10,819,750
A motor vehicle occupant who is killed is said to result in $11,556 in medical costs and $10,600,000 in non-medical costs, totaling $10,611,556
I haven’t figured out why the pedestrian has a lower non-medical cost.
A note on count differences
You may notice that the injury counts in the “Costs of these crashes” table differ slightly from the totals in the “killed or injured” summary above it. This is expected and I will try to reconcile them 1:1 soon. The two figures come from two Chicago Police Department datasets and may be modified at certain times in ways that my import system does not catch. They differ by a small number of records at any given time.
Governor JB Pritzker announced his plan to address the state’s housing shortage in 2026. This is the third year in a row I’ve written about proposed legislation to unlock new housing in Illinois, and this should be the year – the governor and General Assembly leadership are fully aligned since they, together, introduced bills cover six major land use, zoning, and housing development reforms.
Pritzker’s budget address on Wednesday covered a wide range of housing issues in four minutes:
the size of the shortage (227,000 new homes are needed by 2030 to keep up with demand)
everything is too damned expensive! rent is too high!
not enough homes are being built
redlining played a role in housing being built less often in certain areas
regulations inhibit new homes and small homes from getting built
bureaucratic red tape
parking mandates require too much parking that are unused and expensive
Watch the full 4-minute housing speech, part of his hourlong budget address.
I propose some non-exhaustive reasons why the average Illinoisan might want to support these reforms:
There are 6% year-over-year rent increases which is making it hard for Illinois to be a competitive place to maintain its population and its services. Population loss results in higher costs for everyone because services and pensions are paid for by fewer people.
I want Illinois to lose as few Congressional seats as possible in 2030.
It encourages new development which spreads the tax burden onto more taxpayers and lowers it for any given taxpayer.
Ask your legislator to support the BUILD plan by sending them a letter. All you have to do is enter your address and the modify the subject line.
It’s a whole set of reforms to lower housing costs
To resolve these issues, Gov. Pritzker is working with legislative leaders in the Illinois House and Illinois Senate to adopt a package of bills:
In cases where a municipality cannot review a building permit quickly enough an applicant could hire a third-party reviewer. The municipality would have to complete its initial plan review within 15 business days for a one or two-family house, and within 30 business days for “any multifamily, mixed-use, or commercial project”. Each subsequent review cycle would need to be completed within 10 business days.
Additionally, the bill would set inspection standards, specifically requiring a municipality to perform inspections within two business days of the request. Applicants could also use third-party inspector if the municipality does not meet the standard. Municipalities cannot charge additional fees if an applicant exercises this right, and qualified third-party reviewers and inspectors would not be permitted to charge more than the municipality’s fee.
Finally, the bill sets qualification, conflict of interest, and auditing standards, and the bill would also apply to home rule municipalities.
This is a big deal and is the key to unlock the solution to the housing shortage in Illinois. It would allow multifamily housing as of right on all lots that have a minimum area of 2,500 s.f. (To give some context the most common residential lot size in Chicago is 3,125 s.f. and in Oak Park the average residential lot ranges between 4,000 s.f. and 13,000 s.f. depending on the zoning district.)
The bill would permit between two and eight units of housing per lot in a residential zoning district, depending on the size of the lot. It would also permit new housing types that most municipalities ban:
Detached courtyard housing. This would allow a front house and an equal size rear house, which Chicago has vintage examples of and some architecture firms have proposed as part of the Missing Middle Infill Housing initiative, but the Chicago zoning code does not permit)
Future Firm, a design studio based in Chicago, created this concept that places two detached houses on a single property in Chicago. The current zoning code there does not permit more than one principal building per zoning lot, so if this were to get built the two houses would have to share some part of their structures.
What are some potential impacts?
In Chicago, there are 14,148 vacant lots that are zoned in a way that bans multi-family housing. If 5 percent of those were developed each year with a two-flat that would reduce the city’s housing shortage by 1,415 homes annually. (Chicago has seen an average of 4,357 new homes permitted from 2023-2025.) These zoning districts are pretty broadly distributed in Chicago, and overlap with all kinds of school attendance boundaries and near all kinds of amenities.
In Naperville, there are 35,449 (57 percent of the parcels in the city and 86 percent of parcels that allow residential uses) lots that ban multi-family housing. A minority of those would be improved to have two-family houses which would go a long way to increasing opportunity for Illinoisans (while also increase Naperville’s property tax revenues).
That’s almost too simplistic (and perhaps a bit optimistic) because the bill would permit more housing types than Chicago currently allows, like the detached courtyard housing – these new options would respond to the desire for lower-cost detached housing, increasing or maintaining the density on blocks where deconversions and teardowns are common.
The need for housing extends beyond Chicago and Oak Park. I ran this exercise here because it’s where I have the easiest access to high quality property and zoning data. Every town needs additional housing and additional housing types – for its existing residents and for future residents. Every town with transit service especially needs more housing, because more people should be allowed to take advantage of that service and that public investment.
Four two-flats in Logan SquareA courtyard-style building (but without the courtyard)
A municipality would not be allowed to require more than 0.5 automobile parking spaces per multifamily dwelling unit or more than one automobile parking space per single-family home.
And parking mandates would be eliminated for several uses:
individual dwelling units that have an area smaller than 1,500 s.f.
affordable housing developments
assisted living developments
ground floor non-residential uses in mixed-use buildings
when converting a building from non-residential to residential use
The standards would also apply in home rule communities.
Residential buildings up to six stories, with a maximum of four dwelling units per floor, an automatic sprinkler system, and automatic door closers, would be permitted to have a single interior exit stairway (“single stair”). Small multifamily buildings with a single means of egress are as safe or safer than those with more than one.
A typical new apartment building in Illinois has a “double loaded corridor” layout, which has a high apartment per stair ratio. The smart stair option in the center, not currently permitted, has a much lower apartment per stair ratio. The graphic on the right shows that a single stair building can have more variation in unit layouts and sizes (number of bedrooms).
The benefits improve quality of life by making it easier to design multi-bedroom and family-size homes with additional windows for more natural light, and inset porches (allowing for cross-breezes!) because space isn’t needed for a corridor to connect every unit to a second stair way. Homes are closer to the exit in these buildings. Plus, it makes it easier for small, multifamily buildings to “pencil” (make financial sense to undertake) on infill lots which tend to have higher land values.
Note about exiting: at the time of writing I live in a 450-unit apartment building that has five stairs that lead to two exterior stairs (and then there are more stairs after that). I counted that it takes about 220 steps (I have a long stride) to reach the ground; it took me 1 minute and 21 seconds to go from my apartment door, down the stairs, and over to the exterior exit. It takes a little bit more time to descend the last stair to the ground. In a single stair building, that would be limited to 20 feet – far less than the 600-or-so feet in my current abode.
Further reading:
Minnesota study on fire risk of buildings with a single stair compared to buildings with more than one store
Do I even have to say what this is about? The bill would permit accessory dwelling units in all zoning districts that permit residential uses. The state ADU bill, as written in HB5626, could possibly invalidate the labor requirements for coach houses in Chicago (emphasis added):
(1) Each municipality shall permit accessory dwelling units in all zoning districts that permit single-family dwellings without additional requirements for lot size, setbacks, aesthetic requirements, design review requirements, frontage, space limitations, or other controls beyond those required for single-family dwelling units without an accessory dwelling unit.
The state would create formulas that set maximum impact fees, relative to the impact (i.e. number of students, domestic water and sewer, etc.) and incorporate certain unique contexts, to establish certainty for home builders. Municipalities, include those with home rule authority, would have to adopt the formulas within 30 months after the bill’s effective date.
The House has this package in a single omnibus bill: HB 5626.
Volunteers and Rep. BucknerAHIL volunteers at the Springfield Amtrak station
Abundant Housing Illinois volunteers were in Springfield yesterday to listen to Governor Pritzker’s budget speech and to push for bold housing solutions to reduce the housing shortage – evident by continually rising prices – that persists across the state.
The new bills that Governor Pritzker’s office announced today – collectively called BUILD – will have a big impact on permitting new starter homes and allowing multi-family housing all over the state, among other changes to speed up housing construction. These bills will have the biggest effect on reducing housing costs when passed collectively.
Update: City Council adopted a 135% expansion of the ADUs eligibility area with options to go citywide, on September 25, 2025.
Abundant Housing Illinois has put together a bunch of pro-ADU events this month – two of our own, one with a partner, and one is a City Council meeting – in anticipation of the vote on September 25, 2025.
Tuesday, 9/23/25 House+ADU tour in Woodlawn. RSVP is required because capacity is limited. This is a members-only event but there are promo codes for Abundant Housing Illinois members (check the Slack) and for 20th Ward residents (ask me).
The house tour is a 3-block away from the Cottage Grove ‘L’ station in Woodlawn, and the address will be provided after you RSVP.
Thursday, 9/25/25 The City Council meeting where I expect ordinance SO2024-0008918 to be approved! We’ve got 18 people signed up so far to go.
Finally, our ADU petition. We’re trying to collect 500 more signatures to deliver to City Council.
