When your water heater quits, you do not have time to read a 3,000-word essay before the cold showers start. So here is the short version up front: most St. Louis homeowners pay between $1,300 and $1,900 for a standard tank water heater replacement, and tankless installations run higher, often $3,000 to $5,600 depending on the unit and the work involved. The rest of this guide explains what drives that price, how to know when it is time, and what the job actually looks like when a licensed plumber handles it.
Authority Plumbing & Drain installs and replaces water heaters across the St. Louis metro every week, from Warrenton out to Ballwin, Manchester, Ellisville, Chesterfield, and Wildwood. Here is everything you need to know before you buy.
How Much Does Water Heater Replacement Cost in St. Louis?
A water heater replacement in the St. Louis area generally costs between $600 and $3,100, with most standard installs landing in the middle of that range. The final number comes down to three things: the type of unit, the size you need, and the condition of your existing setup.
For a typical 50-gallon tank, which is the most common size in St. Louis homes, here is what you can expect to pay installed:
| Tank Size | Gas Water Heater Installation Cost | Electric Water Heater Installation Cost |
|---|---|---|
| 30 gallon | $1,000 to $1,400 | $900 to $1,300 |
| 40 gallon | $1,100 to $1,400 | $1,000 to $1,400 |
| 50 gallon | $1,300 to $1,900 | $1,300 to $1,700 |
| 75 gallon | $1,900 to $2,400 | $1,800 to $2,300 |
| 80 gallon | $2,000 to $2,500 | $1,900 to $2,400 |
These figures cover the unit, labor, and the standard parts a code-compliant install requires. The water heater itself usually accounts for $400 to $2,100 of that total, and the labor to install it adds another $200 to $1,000 for a tank model.
The good news for local homeowners: replacing an aging, failing water heater is one of the better returns you can get from a plumbing investment. In St. Louis, the return on a new water heater can reach 90 percent, especially when you are replacing a unit that has started racking up repair bills.
What Goes Into Water Heater Installation Cost?
Two homes on the same street can get two very different quotes, and it is not because one plumber is gouging you. Water heater installation cost depends on factors that have nothing to do with the box itself:
- Fuel type. Gas units typically cost a little more upfront than electric but run cheaper month to month. If you are switching fuel sources, expect added cost for new gas lines or electrical work.
- Location and access. A unit tucked in a tight basement corner or hauled up a flight of stairs takes more labor than one sitting in an open garage.
- Code upgrades. Older St. Louis homes often need a new expansion tank, an updated drain pan, proper relief valve discharge piping, or venting corrections to meet current code. These are not upsells. They are required, and a licensed plumber will not skip them.
- Permits. More on this below, but the permit is a real line item.
- Removal and disposal. Hauling away your old tank is part of a complete water heater installation, and reputable plumbers fold it into the quote.
Labor alone usually makes up 30 to 50 percent of a hot water heater replacement cost, which is why a quality install matters so much. The unit is only as good as the hands that put it in.
Signs You Need a Water Heater Replacement
Most water heaters do not die overnight. They warn you first, often weeks or months ahead. The quick list to watch for: rusty or discolored hot water, water pooling around the base, rumbling or popping noises, hot water that runs out fast, a unit older than 10 years, and repair bills that keep stacking up. Any one of these is worth a call, and more than one at once usually means it is time to plan a replacement.
We wrote a full breakdown of each warning sign and what to do about it, so if you want to dig into whether your unit is actually failing, read our guide on the signs your water heater is about to fail in St. Louis. The rest of this article assumes you already know it is time and you are weighing the cost and your options.
How Long Does a Water Heater Last?
A standard tank water heater lasts 8 to 15 years in the St. Louis area, though our hard water tends to push units toward the shorter end of that range. Tankless water heaters last longer, usually 10 to 20 years, because there is no tank sitting full of mineral-heavy water day and night.
If your unit is creeping past the 10-year mark, it is worth getting it inspected even if it seems fine. Catching a tired water heater early lets you replace it on your schedule instead of during a holiday weekend when the house is full.
Tank vs Tankless Water Heater Installation: Which Is Right for Your St. Louis Home?
This is the question we hear most, and the honest answer is that it depends on your home and how you use hot water.
Tank water heaters store and heat 30 to 80 gallons at a time. They cost less to install, they are simple to service, and they are the right call for most St. Louis families. The trade-off is that they take up floor space and they keep heating water even when no one is using it.
Tankless water heaters heat water on demand, so you get endless hot water and lower energy bills over time. Tankless installation costs more upfront, often $1,400 to $5,600 in our area, and switching from a tank to a tankless unit adds labor for venting and gas line upgrades. For larger households or homeowners planning to stay put for a decade or more, the long-term savings often justify the higher water heater installation cost.
If you are torn, the team at Authority Plumbing & Drain will look at your home, your usage, and your budget, then give you a straight recommendation instead of pushing the priciest option.
Do You Need a Permit for Water Heater Replacement in St. Louis County?
Yes. A water heater replacement requires a plumbing permit in St. Louis County, and the permit costs $47. The city of St. Louis charges a comparable plumbing permit fee for the work. A lot of homeowners assume swapping a water heater is exempt, but it is not, and skipping the permit can cause headaches when you sell the home or file an insurance claim.
A good plumber pulls the permit for you and includes the fee in the estimate. That is part of what separates a licensed professional from a handyman doing cash jobs out of a truck. When Authority Plumbing & Drain handles your hot water heater replacement, the permit, the inspection, and code compliance are all built into the job.
How Long Does Water Heater Installation Take?
A straightforward tank water heater replacement in a standard, accessible location takes about two to three hours. If the install involves moving the unit, upgrading gas or electrical lines, or converting to tankless, plan on most of a day. We always give you a realistic timeline before we start so you are not left guessing.
Can You Replace a Water Heater Yourself?
You technically can, but for almost every St. Louis homeowner it is not worth the risk. A water heater replacement involves gas connections, electrical work, venting, water lines, and code requirements. Get any one of those wrong and you are looking at a gas leak, a flood, a voided manufacturer warranty, or a failed inspection. The labor savings disappear fast when a DIY install goes sideways.
A licensed plumber also pulls the permit, hauls away the old unit, and stands behind the work. That peace of mind is the whole point.
How to Save Money on Hot Water Heater Replacement
You do not have to overpay to get a quality install. A few things help keep your hot water heater replacement cost in check:
- Right-size the unit. Bigger is not always better. A plumber can size the tank to your household so you are not paying to heat water you never use.
- Ask about energy-efficient models. Higher-efficiency units may qualify for rebates and they cut your monthly bills, which softens the upfront cost over time.
- Replace before it fails. Emergency replacements cost more and leave you with fewer choices. Planning ahead lets you shop.
- Get the permit and do it right the first time. A code-compliant install protects your home value and avoids expensive corrections later.
- Maintain the new unit. Flushing the tank to clear St. Louis hard-water sediment extends its life and protects your investment.
Why St. Louis Homeowners Trust Authority Plumbing & Drain
Authority Plumbing & Drain is a locally owned plumbing company serving the St. Louis metro from our home base in Warrenton, MO. Our licensed plumbers handle water heater replacement, water heater installation, and tankless conversions for homeowners across St. Louis County, St. Louis City, St. Charles, Ballwin, Manchester, Ellisville, Chesterfield, Wildwood, and the surrounding communities.
When you call us for a water heater, you get honest pricing, code-compliant work, the permit pulled for you, and your old unit hauled away. No upselling, no surprise fees, just hot water back on the same day whenever possible.
Need a water heater replacement in St. Louis? Call Authority Plumbing & Drain at (314) 326-1160. We are open Monday through Friday, 7am to 7pm, and ready to help you get hot water flowing again.
Water Heater Replacement FAQ
How much does it cost to replace a water heater in St. Louis?
Most St. Louis homeowners pay between $1,300 and $1,900 for a standard tank water heater replacement. Smaller 30 and 40 gallon units cost less, and larger 75 to 80 gallon tanks or tankless systems cost more. Tankless installation often runs $3,000 to $5,600 depending on the unit and the work required.
Is a hot water heater replacement worth the cost?
In most cases, yes. A new water heater in St. Louis returns up to 90 percent of its cost in value, and a modern unit cuts your energy bills while ending the cycle of repair calls on an aging tank.
Do I need a permit to replace a water heater in St. Louis County?
Yes. A plumbing permit is required, and it costs $47 in St. Louis County. A licensed plumber will pull it for you and include it in the estimate.
How long does a water heater last?
Tank water heaters last 8 to 15 years, and tankless units last 10 to 20 years. St. Louis hard water can shorten a tank’s life, so units past 10 years are worth inspecting.
Should I get a tank or tankless water heater?
Tank models cost less to install and suit most households. Tankless units cost more upfront but deliver endless hot water and lower energy bills over time, which makes them a strong choice for larger homes or longer-term owners.
How fast can you replace my water heater?
A standard tank replacement usually takes two to three hours, and we aim to restore your hot water the same day. Call Authority Plumbing & Drain at (314) 326-1160 to schedule.