Over the years, more than 175 water quality treatment centers have been closed through MSD’s sanitary sewer expansion program. Their sizes range from the large Okolona and Shively plants to "package" plants designed to serve individual residences and businesses. The list below includes most of the plants closed through 1996. The expansion program also has eliminated thousands of individual septic tank systems.
| Allied Ready Mix | Greenspring Subdivision | Sanders Elementary School |
| Anderson Sanitation | Gulf Oil Station, 12000 U.S. 60 | Shady Villa Subdivision |
| Arby’s Roast Beef, 2140 Old Shepherdsville Road | Hardy’s Inc., 1217 Outer Loop | Shallow Creek |
| Associated Transport | Helck Ave. House, 1324 Helck Ave. | Shively waste water treatment plant |
| Barbour Manor | Henderson Electric | South Central Bell, 4711 Progress Blvd. |
| Beth Haven Baptist Church | Heustis Auto Supply | South Central Bell, 3910 East Pages Lane |
| Bio-Med | Holiday Manor | South Park Country Club |
| Brookfield Mobile Home Park | Holland Motor Express | South Park Drive-In |
| Candlelight Subdivision | Hollyvilla 1 | Southland Mobile Home Park |
| Cardinal Aluminum | Hollyvilla 2 | Southwest Jefferson County Hospital |
| Cardinal Extrusion | Holtman residence, 62 Indian Hills Trail | Speedway |
| Cardinal Mobile Home Park | Hounz Lane Park | Spring Creek |
| Cedar Heights Mobile Home Park | Idlewood | Spring Lake Farms |
| Cedar Lake Park | Industrial Subdivision | Spring Valley Estates |
| Central Glass Co. | Iroquois Park Riding Stable | Springdale Subdivision |
| Central State Hospital | J&L Oil Station, 4565 Poplar Level Road | St. Anthanasius Church |
| Charleswood | Jefferson Piping & Heating | St. Jerome Church |
| Chenoweth | Kennedy Elementary School | St. Margaret Mary |
| Chevron Station, 8717 Westport Road | Kentucky Children’s Home | Sts. Thomas & Vincent Orphanage |
| Christian Assembly | Kentucky Fried Chicken, 12012 U.S. 60 | Standard Country Club |
| Cinderella | Kentucky Military Institute | Stauble Machine & Tool |
| Clark Services | Leemont Acres | Stonestreet Elementary School |
| Clifford, Inc. | Louisville Boat Club | Sungold No. 1 |
| Confederate Acres | Louisville Country Club | Sungold No. 2 |
| Convenient Food, 11803 U.S. 60 | Louisville Optical Co. | Sunoco Service Station, 11514 U.S. 60 |
| Convenient Food, 8320 Old Third Street Road | Louisville Regency | Sunoco Service Station, 12005 U.S. 60 |
| Daring Plumbing Co. | Lyndon Baptist Church | Sunoco Service Station, 5505 Outer Loop |
| Dean’s Tire Service | Lyndon Vocational School | Tarrytowne |
| Dorsey Woods No. 2 | Madison residence, 8314 Arnoldtown Road | Terry’s Chevron Station, 1357 Gilmore Lane |
| Dorsey Woods Subdivision | Mansville Plastic | Texaco Service Station, 12016 U.S. 60 |
| Douglass Hills Subdivision | Mason-Dixon Co. | Third Street Sanitation |
| Dove Creek Subdivision | Maytag Laundry, 8027 Vinecrest Ave. | Thornhill Subdivision |
| Dunn Elementary School | Middletown Beauty Shop | Thoroughbred Machine |
| Durex | Middletown Elementary School | Timothy Hills Subdivision |
| Eastern High School | Middletown Manor | Tin-Dor Estates Subdivision |
| Eastland Shopping Center | Minor Lane Heights | Transit Oil Co. |
| Elysian Fields | Muddy Fork | Treasure Island East |
| Evergreen Investments | Murray Hills Subdivision | Treasure Island West |
| Exxon Service Station, 3620 Buechel Bypass | Netherton Place | Tree Line Estates |
| Fairdale Elementary School | Newmarket | Tuton Building |
| Fairdale High School | Norton Elementary School | University of Louisville Shelby Campus |
| Fairdale South Park | Ohio Transmission & Pump Co. | Valley High School |
| Fairhaven Mobile Home Park | Okolona | Valley Village Subdivision |
| Faith Lutheran Church | Old Brownsboro Place | Villa Anna Subdivision |
| Falls Creek | Ormsby Village | Village Square Shopping Center |
| Featherlite Pre-Cast | Outer Loop Wastewater Facilities | Vulcan Materials |
| Fern Creek | Pepper Mill Restaurant | Welker Company |
| Fern Creek High School | Plantation Hills No. 2 | Weslo, Inc. |
| First National Bank, 12009 U.S. 60 | Plantation Subdivision No. 1 | Westcreek Apartments |
| Foxboro Subdivision | Pleasure Ridge Park High School | Westport Middle School |
| Freeman residence, 3725 Bishop Lane | Ponderosa Mobile Home Park | Whale Oil Station, Hurstbourne Lane |
| Frey’s West | Poodles By George | Whispering Hills |
| Friendly Hills | Poplar Level Sewer Construction District | Wilder Elementary School |
| George’s Mobile Home Park | Poplar Park | Wildwood Apartments |
| Glen Hill Manor | Prairie Village Subdivision | Windsor Forest |
| Glengarry Subdivision | Reserve International Services Inc. (Liquid Transporters) | Woodhaven Medical Service |
| Glenmary | Resurrection, Church of the | Woodstone |
| Glenview Hills Subdivision | Reynolds Metals | |
| Glenview Woods | Rolling Hills Subdivision |
MSD History continued - Treatment Plants
