Columbus, Ohio: water and wastewater capital improvement projects
297 line items · $4.2B · starting 2026–2029 · 1 plan
Columbus's published capital plans list 297 water, sewer and wastewater line items with a combined planning budget of $4.2B, of which 186 items worth $2.5B sit in the wastewater and sewer departments. The largest single item is Fourth Water Plant at $548M (2025–2028). The ten largest items are listed below; the full list with descriptions and page references is in Klarifi.
A capital improvement plan (CIP) is a city’s multi-year budget for building and replacing infrastructure. The water, sewer and wastewater sections list each project with its budget and the years it is funded, which makes them the earliest public signal that a plant, pump station or pipe network is about to be upgraded, usually two to four years before a contract is awarded.
The largest water and sewer projects in Columbus
| # | Project | Department | Type | Budget | Years |
|---|---|---|---|---|---|
| 1 | Fourth Water Plant | Water Supply | Water treatment plants | $548M | 2025–2028 |
| 2 | Williams and Castle Interceptor | Sewer | Force mains and interceptors | $362M | 2025–2029 |
| 3 | Three Creeks Relief Tunnel | Sewer | — | $250M | 2025–2028 |
| 4 | SWWTP Effluent Pump Station Expansion | Wastewater | Pump stations | $228M | 2027–2029 |
| 5 | Fourth Water Plant Transmission Main | Water Distribution | Water treatment plants | $218M | 2025–2029 |
| 6 | SWWTP Far East Train | Wastewater | — | $215M | 2025–2027 |
| 7 | DRWP GAC Improvements | Water Supply | Membranes and filtration | $154M | 2025–2028 |
| 8 | Southerly Stormwater and Floodplain Improvements | Wastewater | Stormwater and flood resilience | $109M | 2027 |
| 9 | Upground Reservoir - Site 3 | Water Supply | Storage tanks and reservoirs | $100M | 2029 |
| 10 | Water Main Rehabilitation | Water Distribution | Water mains and distribution | $96M | 2025–2029 |
287 more line items in Columbus, with descriptions and contacts
Klarifi holds every Columbus line item with its description, the page it appears on and the source document, plus 1 verified contact at the city’s treatment plants. Track new plans as they are adopted and compare with similar projects in other cities.
Planned spend by start year
Before 2026
$2.8B
140 items
2026
$661M
73 items
2027
$454M
34 items
2028
$96M
26 items
2029
$169M
24 items
By department
| Department | Line items | Budget | Share |
|---|---|---|---|
| Wastewater | 54 | $1.2B | 29% |
| Sewer | 132 | $1.3B | 31% |
| Water Supply | 75 | $1.2B | 29% |
| Water Distribution | 36 | $465M | 11% |
Project types in Columbus's plan
Wastewater treatment plants in Columbus
5 publicly owned treatment plants in Columbus with 31 permit violations in the last three years. Each profile shows flow, permit, technology and compliance data.
| Plant | Avg flow (MGD) | NPDES | Violations (3y) |
|---|---|---|---|
| Aqua Ohio Water Co Inc - Blacklick WWTP | 0.72 | OH0036021 | 8 |
| Darbydale WWTP | 0.12 | OH0130923 | 15 |
| Enchanted Acres Mhp | 0.08 | OH0036722 | 1 |
| Odotrest Area 04-42 WWTP | 0.0016 | OH0088137 | 7 |
| Jackson Pike Wastewater Treatment Plant | — | OHL024732 | 0 |
Other Ohio cities with capital plans
Columbus capital plan questions
Sources and methodology
Budgets and years are as published in Columbus’s capital improvement plan or adopted budget. Klarifi extracts the water, sewer and wastewater line items from the published document, keeps the page reference for each one, and assigns a project type from the title and description with a keyword classifier. Figures are planning budgets, not awarded contracts, and can change when a plan is re-adopted.
Documents: CIP 2024–2029 (297 line items).
Data refreshed September 11, 2026.