Bathroom faucet installation looks straightforward until the hole configuration doesn't match the faucet, the shutoff valves won't close, or the supply lines are the wrong length. STL Plumbing Pros confirms the sink configuration and valve condition before any faucet is installed — preventing the most common installation problems. We supply and install, or install customer-supplied faucets. Same-day available for most installations.
When Do You Need a New Bathroom Faucet?
Style or finish upgrade — replacing builder-grade fixtures with brushed nickel, matte black, or oil-rubbed bronze.
Faucet body is corroded or cracked — porcelain-coated or chrome-over-brass faucets can corrode through to the base metal.
Repair cartridge is unavailable — discontinued faucet brands where replacement cartridges are special-order or no longer manufactured.
Renovation — new vanity, countertop, or sink requiring a new faucet to match the new configuration.
Accessibility upgrade — replacing twist or two-handle faucets with a single-lever for ease of operation.
Faucet Selection — What to Confirm Before Buying
Number of sink holes
Single-hole sinks require a single-hole faucet or a deck plate. Three-hole sinks (standard 4-inch center spread) accept widespread or centerset faucets. Widespread faucets (8–16 inch spread) require three separate holes. Buying a faucet for the wrong hole configuration is the single most common installation problem — we confirm before any purchase is made.
Faucet type compatibility
Vessel sinks (countertop-mounted basins) require a taller faucet body with a higher spout reach to clear the basin rim. Standard drop-in or undermount sinks use standard-height faucets.
Shutoff valve condition
The supply shutoff valves under the sink need to close completely. In older St. Louis homes with original gate valves or compression shutoffs, these may not close fully after decades without operation. We assess them before installation and replace if needed.
In pre-1970 St. Louis homes with original galvanized supply lines, the supply line pressure to the bathroom faucet may already be reduced from interior pipe corrosion. A new faucet installation is a good time to assess supply line condition.
Our Installation Process
Confirm Hole Configuration and Valve Condition
Measure the sink hole configuration — number of holes, center spread, hole diameter. Confirm shutoff valve operation. If valves are borderline, we discuss replacement before proceeding. If existing supply lines are over 10 years old, we include new supply lines.
Remove Old Faucet
Shut off supply valves, disconnect supply lines, remove the mounting nut from below the sink, lift out the old faucet, clean the sink surface at the mounting area.
Install New Faucet and Test
Install per manufacturer instructions — mounting, supply line connections, aerator installation. Restore supply, run hot and cold at full pressure, confirm no leaks at any connection, confirm aerator flow is unrestricted, handle operation is smooth through full range.
What Does Bathroom Faucet Installation Cost?
| Service | Price | Details |
|---|---|---|
| Install-only (customer-supplied faucet) | $150–$250 | Includes old faucet removal, new supply lines, and installation. |
| Supply and install (we provide the faucet) | $300–$600 | Builder-grade to mid-range single-hole or centerset faucets. |
| Shutoff valve replacement | $125–$250/valve | Often needed in pre-1980 homes with original shutoffs. |
| Supply line replacement | Included | New braided stainless supply lines on every installation. |
| Deck plate for hole mismatch | $25–$60 | Covers unused holes if new faucet uses fewer than the sink has. |
Why Choose STL Plumbing Pros?
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Hole Configuration Confirmed Before Install
We confirm the sink hole configuration before recommending or installing any faucet. The most common installation problem — buying a 3-hole faucet for a single-hole sink — is prevented at this step.
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New Supply Lines Standard
We replace the supply lines on every faucet installation. Reusing 10-year-old braided supply lines under a new faucet is a leak waiting to happen — new lines are included.
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Valve Assessment Included
We test the shutoff valves before installation. Valves that don't close fully on a pre-1980 St. Louis home are identified before the faucet is out, not after.
What Our Customers Say
"Wanted to upgrade the bathroom faucet finish to brushed nickel. Plumber confirmed my sink had three holes and recommended the right faucet style, installed it in under an hour. New supply lines included. Clean, professional."
"Old faucet was leaking and the cartridge wasn't available anymore. Plumber replaced the whole faucet — brought a few options to choose from, installed my choice, disposed of the old one. Really convenient."
"The shutoff valves under my bathroom sink wouldn't close — plumber replaced them before installing the new faucet. I hadn't known they were an issue. Glad it was identified before it became an emergency."
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Ready for Bathroom Faucet Installation?
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314-237-0332