When your water heater is leaking, corroding, or simply past its useful life, STL Plumbing Pros handles the complete replacement — drain, disconnect, remove, install, connect, test, and dispose of the old unit. We replace tank with tank, convert tank to tankless, or switch fuel types. For tankless conversions, gas line upsizing may be required. Same-day replacements available for standard installations.
Signs It's Time for Replacement
Tank is leaking — water pooling at the base means internal corrosion. Not repairable.
Unit is 10+ years old — approaching or past expected lifespan for St. Louis water conditions.
Rust-colored hot water — corroded tank walls contaminating your water supply.
Frequent repairs — when repair costs keep adding up, replacement is more economical.
Insufficient hot water despite a working unit — sediment buildup has reduced effective tank capacity.
Our Replacement Process
Evaluate & Quote
We assess your current unit, discuss replacement options (same type, upgrade, or conversion), and provide a complete written quote before starting.
Remove & Replace
Drain and disconnect the old unit, position and connect the new water heater, handle all plumbing, gas, electrical, and venting connections.
Test & Clean Up
Fill, test for leaks, verify hot water delivery at fixtures, set thermostat, and remove the old unit. Your space is left clean.
Replacement Pricing
| Service | Price | Details |
|---|---|---|
| Standard tank-to-tank replacement (40–50 gal) | $1,200–$2,400 | Same fuel type, same location — most straightforward swap. |
| Tank-to-tankless conversion | $4,000–$6,500 | Includes gas line upgrade, venting changes, and old tank removal. |
| Electric-to-gas conversion | $2,500–$4,000 | Requires new gas line run to water heater location. |
| Old unit removal and disposal | Included | We drain, disconnect, remove, and dispose of the old unit. |
Why Choose STL Plumbing Pros?
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Same-Day Replacement
We stock common units and can often complete standard replacements the same day you call.
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All Conversion Types
Tank to tank, tank to tankless, electric to gas — we handle the complete conversion including all infrastructure changes.
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Permits Handled
We pull the required plumbing permit and ensure the installation passes inspection. No loose ends.
What Our Customers Say
"Old water heater started leaking Saturday night. They were there Sunday morning, had a new one installed by noon. Incredible response."
"Replaced a 15-year-old gas water heater. Clean removal, new unit installed, old one hauled away. Simple and efficient."
"They gave me honest advice about whether to repair or replace. The repair would have been $400 on a 12-year-old unit — replacement was the right call."