By Bobby Tanzilo Senior Editor/Writer Published Nov 07, 2023 at 9:01 AM

Listen to the Urban Spelunking Audio Stories on 88Nine Radio Milwaukee.

The City of Milwaukee has two water treatment plants that bring clean drinking water from Lake Michigan in the taps of 867,000 people, not just in Milwaukee, but in communities from Brown Deer to Butler, Wauwatosa to West Milwaukee, and even to Waukesha.

The main entrance.

If one of the plants – on Howard Avenue – looks almost like a low-slung 1950s office building – the Linnwood Water Treatment Plant, on the lakefront at 3000 N. Lincoln Memorial Dr., is an entirely different story.

Completed in 1939, this Art Deco limestone gem designed by Chicago’s Alvord, Burdick, and Howson, is like a temple to good government, a monument of municipal responsibility and a towering achievement of Milwaukee’s socialist past.

Built as a Depression-era Public Works Administration (PWA) project under the eye of longtime Milwaukee Mayor Daniel Hoan, the Linnwood Water Treatment Plant is also a beloved architectural icon of the city, with its instantly recognizable clocktower.

Steps up to the coagulation beds.X

But while most of us have seen, and likely marveled, at the building’s lovely exterior – with its Lannon stone cladding and multi-colored clay tile roof – very few get to venture inside, due to tight security that works to keep our water supply safe.

Originally, public tours were available, but World War II put an end to that, and also resulted in the fence that encloses the property. The Sept. 11, 2001 attacks served to further increase security.

speed linesX

After years of asking, I was finally allowed inside to show you what it looks like inside, and what a place it is – one of the real Art-Deco-era gems of Milwaukee.

But first, a little history...

In the early days, around 1840, clean water supply was a private enterprise, but within a few years, there were calls for a municipal system and proposals soon followed, but action was slow.

lake view
A view of the lake from the roof.

“In 1866, the Milwaukee Sentinel noted that it was necessary to walk more than half a mile from the business district to find a pump to supply water that was ‘pure and wholesome to the taste and smell’,” notes the Encyclopedia of Milwaukee.

Dirty water led to disease and with sewage and trash and industrial waste – to say nothing of the countless unlined outhouse toilets in backyards throughout the city – running into local waterways, clean water wasn’t easy to find.

Plus, the city needed water for laundry, cleaning the streets, firefighting, industrial use and more. Cisterns to collect rainwater just weren’t doing the trick.

Pumping station
The old North Point Pumping Station and water tower. (PHOTO: Milwaukee Water Works)

The state approved a tax so that the city could fund a system and in the early 1870s, Milwaukee got a pumping station (now razed), reservoir (defunct, but its butte remains as a park) and water tower (which still stands), as well as underground mains to deliver water to customers.

But cleanliness remained an issue and among the many ideas for ensuring clean water was construction of a water treatment plant.

“By 1931 the effects of the Great Depression on Milwaukee’s workers were severe enough that constructing a filtration plant won approval as a way to increase employment,” the Encyclopedia notes. “A loan from the federal Reconstruction Finance Corporation underwrote costs.

“It took nearly four years, and a months-long episode of foul-smelling water resulting from the combination of chlorine and industrial waste to overcome the Non-Partisans’ (who preferred a sewage treatment plant) objections to a filtration plant.”

A rendering of the building, painted by John Taylor. (PHOTO: Milwaukee Water Works)

Work to build the plant began in 1934 and five years later, the facility – which cost about $5.5 million to construct – was fired up. The plant was located on 24 acres of land reclaimed from the lake with fill.

About 30 percent of the cost was covered by the Federal Emergency Administration of Public Works, and the project employed many at a time when work was nigh impossible to find.

The staircase up to the lab in the tower.

When the building opened, according to a long-unpublished city guide created by the Federal Writers’ Project, “the building house(d) service and administration departments, the chemical tower six stories high, 32 filter beds each 38 by 57 feet, and five pumps capable of handling 275,000,000 gallons of water every 24 hours.

“A labyrinth of tunnels, basins and corridors, three clear-water wells with a combined capacity of 30 million gallons and four coagulation basins, each 149 by 375 by 28 feet, are all underground.”

In fact, the guide noted, the, “two-story brick and Lannon stone building in modernized Gothic style is visible from (Lincoln Memorial) drive but most of the plant is underground.”

Post-war growth in the area required further capacity and the Howard Avenue plant went online in 1962.

How does it work?

“The City of Milwaukee improved the water filtration system by transforming the filter system as well as changing the management of the filters,” wrote Michelle Gonzalez and Barbara Gonzalez in The Confluence. “Sand filtration was first used to filter out particles from the flowing water. It consisted of three feet of sand and rocks, however, the new filtration system is made of anthracite coal, high in carbon content, which is added on top of sand.  

Former and current filtration media.
Former (left) and current (right) filtration media.

This multi-layered filtration system was implemented in both Milwaukee water plants. They effectively remove small particles from the water and help reduce the risk of cryptosporidium ending up in the water coming from your faucet.”

The Encyclopedia of Milwaukee, which adds, “additionally, both plants were retrofitted to use ozone as a disinfectant, (supplementing) chlorine. This redesign was a Milwaukee innovation; other systems wishing to update their own purification plants use the Milwaukee plants as a model.”

Part of the ozonation system.

The City of Milwaukee Water Works says that since the 1993 outbreak, it has invested more than $508 million in the city’s water supply infrastructure.

An old water intake – called the Love Rock because three artists had spray-painted the word “Love” on what looked like a small rocky island offshore – was blown up in 1986 because too many people were risking their lives swimming and boating out to it.

Love Rock
The Love Rock. (PHOTO: Milwaukee Water Works)

That one had supplied water to the old water intake plant and operated from 1895 until 1918, sitting on standby until 1964, when it was completely decommissioned.

That initial decommissioning took place because the city built a new Lannon stone water intake building along the lakefront in 1918. That building is still used as an intake point, as well as the point at which Linnwood sends water out to the Northpoint and Riverside Pumping Stations, though now sits west of the Linnwood plant, many yards from the water’s edge.

These days, water is sucked in via a 6,565-foot (or 1.25-mile) intake pipe that opens where the lake has a depth of about 62 feet.

“They kept going farther north because of the unfortunate influences of the harbor,” says Linnwood Plant Manager Daniel Welk.

“The rivers were bringing things in that they didn't want, and also they built the flushing station to flush the river. They were proud about cleaning up the river in 24 hours, but you just sent it to your drinking water.”

Inside the intake building there’s a 12-foot tunnel that slopes down northeast from Linnwood out into the lake.

Two of the numerous decorative panels in the building's lobby.

“The intake structure is sitting at the bottom of the lake connected to that shaft,” Welk explains.

Welk says crews dive periodically to inspect and, if necessary, clear the intake.

The Texas Avenue intake on the South Side brings water to the Howard Avenue Water Treatment Plant, and that one goes more than two miles offshore, at a depth of around 45 feet. It, too, was moved to avoid the the harbor water.

“Depth wasn't as much of a consideration there,” Welk says. “They had done a harbor study and just looked at where were they were finding the pollution and that spot seemed to be the one where it was reduced by 90 percent or something to that effect.

“So, we moved to a better spot outside of the influence of the harbor, sitting out farther northeast, but 11,000 feet out instead of 7,600 feet out. That was a huge improvement in water quality for the Howard plant. And, to be honest, the Deep Tunnel made a huge difference, too, with next to nothing (in terms of) overflows.”

Once water enters the system, the process at Linnwood takes about 24 hours, Welk says.

How long it takes the water to get to your house, depends on system demand and how far you live from the plants.

The process begins with ozone disinfection in which ozone gas is bubbled through the water, destroying microorganisms, helping to prevent disease and controlling taste and smell.

Next, in what is called coagulation and flocculation, aluminum sulfate is added to help particles stick together and form “floc.” That floc settles out of the water in the next phase, called sedimentation.

Then, the water is filtered slowly through two feet of crushed anthracite coal and a foot of sand to remove smaller particles. Afterward, chlorine is added as a disinfectant, and fluoride is added to help ensure healthy teeth.

The treated water is then stored in basins underground until it is needed. While there, a food-grade phosphorus compound is added. This helps prevent pipe corrosion and keeps lead and copper from leeching into the drinking water.

Finally, ammonia converts the chlorine in the water to chloramine, which helps ensure bacteriological protection in the water distribution system.

The treated water leaves the site via pipes nine feet in diameter headed to the Northpoint and Riverside pumping stations. Those pipes are in the same small 1918 building where it comes in from the lake.

There’s also a bypass pipe in case that building should need to come offline at some point.

The vestibule stairs into the lobby.

“There are multiple redundancies throughout the plant,” says Welk, explaining that these alternate routes for water should mean the plan never has to be entirely shut down.

Since the changes were implemented, Milwaukee is often credited with having some of the best drinking water in the country. Seeing the system at work is pretty remarkable.

Going inside, the building’s architecture is no less impressive.

What's it like inside

Inside the main entrance, there’s a vestibule clad in Kasota stone from Minnesota, tiled floors, decorative panels depicting water-related scenes and beautiful brass light fixtures and ornate grilles.

fountain plaque
The fountain spigot plaque.

Up a couple stairs you’re in the main lobby, with more stone, a Vermont marble floor, more panels, a fountain with a spigot that pokes out of a fire hydrant nozzle depicted in a brass plaque, a staircase up to the next level and doorways that lead off to the pump room, stairs down to the lower level and lots of vertical Deco speed (or Empire) lines everywhere.

The fountain and the stairs up to the beds.
The fountain and the stairs up to the beds.

In this space there’s also a glass-doored wooden display case holding some historical gauges and other items, as well as a model of the plant, with a display panel explaining how it works. This lobby is also where the main offices are located.

Through a set of doors you’re on the balcony of the pump room, where you can see the pumps that bring water into the system and others that are used to periodically backwash the system to keep it flowing well.

This multi-story space is impressive, with large windows, more Moderne Deco-ration – heavy on the chevrons here – and another clock, which is synchronized with the one out front.

The oldest of the pumps, from 1938. Still working!

Two of the pumps here are original to the building and some of the others (on at least some of them I noticed the Allis-Chalmers name) are nearly as old, Welk says. Although they need maintenance, of course, he says they rarely need much in terms of repairs.

Back through the lobby, we take the stairs up to the two intersecting corridors that run along the filter beds, of which there are many.

filter beds
Filter beds.
Old gauges, no longer in use.

This space, with its soaring ceiling height, gorgeous green tile everwhere, original (though no longer working) clock-like gauges and, yes, another clock, is like a cathedral to water.

Local tile expert Ben Tyjeski says that the wall units are ashlar terra cotta manufactured by Illinois’ American Terra Cotta & Ceramic Company, but the green matte crystalline tile on the bulkheads and unglazed floor pavers are from the South Milwaukee-based Continental Faience and Tile Company.

One of the filter bed corridors.

It is one of the most glorious spaces in town.


There’s a round well-like opening that looks down into a lower level where there are pipes to bring water in – “1938” can be seen on the floor at the bottom if you peer down – and in the center of the cross is an old attendant’s booth that’s no longer used, but remains intact and in place.

Also just off this corridor is the monitoring area where staff keeps a close eye on the plant and its processes.

A pair of display kiosks show the makeup, and the actual depth, of the current filtration system (anthracite and super-fine, dense sand) and of the earlier method (sand and rocks).

Booth at the intersection of the filter beds corridors.

Flanking the staircase we took to get here are two sets of stairs that lead up to the next level of the central tower, which is where the laboratories are located.

When I ask to see the inner workings of the clock that can be seen on the building’s tower from Lincoln Memorial Drive, we take an elevator up almost ot the top, where we can see part of an the old carbon-based treatment system that was replaced by the current treatment system, as well as the tops of the hoppers into which the powdered chemicals were once loaded into the system.

Again, this is no longer used, but remains in place because the building was literally constructed around it, making it difficult and costly to remove.

Some of the old chemical hoppers in the tower.
The clockworks.

The exterior clock parts – hands and numbers – were replaced a couple decades ago, but the remarkably small mechanism that runs the clock could be original.

Heading back down, Welk takes me in to see the ozonation system, which occupies a low addition at the north end of the site that was added as part of the 1990s upgrades. This building mirrors the architecture of the original plant and is faced in Lannon stone.

Here we can see the equipment that creates the ozone, as well as peek into windows in the giant tanks in which we can see the ozone bubbling into the water.

Outside, we get to peer into the open hatches of one of the four underground sedimentation basins, which is empty so that staff can clean out the sediment, which is pumped to MMSD on Jones Island.


The two other basins, on the opposite side of the building, are full. There is enough capacity and redundancy in the system that the other basins can be used while others are offline for cleaning.

Crews put on hip waders and rain gear and climb down a ladder about 14 feet to the top level of the basin. Then they descend another ladder into the lower level – another 14 feet down – to clean that level.

Welk, who has worked at the plant since the 1980s, has cleaned out those tanks. In fact, he started out mowing the grass above the basins and climbing down into them for clean-out. By now, he’s done most jobs at Linnwood.

We also stop in to meet the staff in the lab.

There’s an area for quick-turnaround tests to make sure everything is hunky dory, and in here there are three cabinets with taps that provide samples from more than two dozen sites in the building.

Some of the many taps in the lab.

There are also facilities for more in-depth study and research, as well as an area for the techs who travel around town collecting samples for testing from sites like firehouses and police stations.

These field samples help make sure the water coming out of the system is as good as the water going into it here at the plant.

To help ensure that, Linnwood and Howard Avenue have a lab staff of about two dozen people.

“Our goal,” says Welk, “is to make sure that regardless of the quality of the water coming in, the quality of the water we’re sending out is consistent.”

Bobby Tanzilo Senior Editor/Writer

Born in Brooklyn, N.Y., where he lived until he was 17, Bobby received his BA-Mass Communications from UWM in 1989 and has lived in Walker's Point, Bay View, Enderis Park, South Milwaukee and on the East Side.

He has published three non-fiction books in Italy – including one about an event in Milwaukee history, which was published in the U.S. in autumn 2010. Four more books, all about Milwaukee, have been published by The History Press.

With his most recent band, The Yell Leaders, Bobby released four LPs and had a songs featured in episodes of TV's "Party of Five" and "Dawson's Creek," and films in Japan, South America and the U.S. The Yell Leaders were named the best unsigned band in their region by VH-1 as part of its Rock Across America 1998 Tour. Most recently, the band contributed tracks to a UK vinyl/CD tribute to the Redskins and collaborated on a track with Italian novelist Enrico Remmert.

He's produced three installments of the "OMCD" series of local music compilations for and in 2007 produced a CD of Italian music and poetry.

In 2005, he was awarded the City of Asti's (Italy) Journalism Prize for his work focusing on that area. He has also won awards from the Milwaukee Press Club.

He can be heard weekly on 88Nine Radio Milwaukee talking about his "Urban Spelunking" series of stories.