One of my ancient gas water heaters just started leaking so I'm looking to replace it and its brother beside it. Located in my garage and 50gallon, gas.

Easily accessible in a large closet in garage.

Anyone have an idea what sort of price I should expect in the DFW area?

So far I have:

$5100
$3100

Both big companies.

If they are easy to get to get two new heaters, gas lines and water lines at the Depot and swap them out. Both will be right around $1,000.

I seem to recall paying about $1500 for 1 unit.

What part of town?

I had 2 guys who worked Kaufman and South Dallas do some work for me. I won't say they were the best guys, but they got it done, permits and everything, for about 1/4 of what United Mechanical bid on the job.

A few miles west of DFW airport.

just replaced a single 50 gal gas unit.
I paid around 1100.
quotes I got were 1300 to 2600 before I found the guy I used.
Even with 2 I can't see it costing as much as you quoted.
We asked in our neighborhood facebook page and got some less expensive local people.
That high one was baker brothers I think.
So if you go with one of those name brand places, I could see the quote you got.

I've used Jennings Plumbing Services in Carrollton before and was happy with them.

If you're up near The Colony I would use CPR Plumbing Services, he is thorough and fair.

Can't help you with the quote amount, sorry, but I would imagine they both would beat the quotes you have.

I'd avoid Berkeys.  I'd wager they're the $5100 quote.

Wow. Good guess. They were middle low for my ac so I thought they would come through for me. Not so much....

If you can change your oil you can do it yourself.

The part most plumbers hate about water heater replacements is getting the old ones out. Mostly because by the time they need replacement the drains are plugged and hard to drain.

One thing to do if replacing it yourself is check the NEW gas line with soapy water for any leaks. If they are the same size the vent stack should work out, just use heat resistant duct tape.

Good thinking. I'm leaning towards DIY currently.

This.

$5100? - tell me they use lube.

I have a heating element out on mine, electric. I could replace the element, but it's 10+ years old. I've replaced them before, gas and electric, and I'll be doing it again.

Gone are the days where you solder/sweat in the fittings. It's all flex hose and threaded fittings with washers. My old house was sweated copper, but a propane torch and a pair of channel locks, that came out. Sweated on threaded fittings, made sure it didn't drip and that was that. It's not exactly rocket science, but people are funny about that kind of stuff, and wanting a licensed plumber to do it. If you see any amount of construction, you'll roll your eyes over what you'll see licensed professionals do. And you'll see all kinds of weird specs for what people think you must have for a pop-off/pressure relief valve.

The biggest bitch is wrestling a big tank in and out of a tight space. I was having back trouble one time, my wife suggested calling over a neighbor to help. Dave was 6'6" tall, former marine, and a few years younger than me. He just bear hugged it and set it in place.

Total Plumbing charges per hour, lets me buy my own stuff for commercial and residential. They were the first place I found that does not do a service call fee, plus flat rate.
972-681-4434