After trying to repair it by removing the plunger rod and either refurbishing or replacing it, I'd dig down around the hydrant to gain access to the connection to the water line. (Depending on your frost depth, beer, pizza and a couple friends might make this, probably the hardest part and what drove that estimate, easier.) If it's just replacing the hydrant, that shouldn't be difficult. The hole will have to be large enough to get down there to do the necessary work. Make sure you leave it based in enough gravel to allow the standpipe to drain when shut off and also that there is nothing connected to the hydrant in freezing weather.

Hopefully your hydrant isn't in a concrete slab.

Thanks! We can't dig it ourselves, but it's not in concrete. We have a couple more local people coming to give us some estimates. Hopefully they'll be more reasonable.

Yes, the quote is high, but I don't think it is that unreasonable. When we built, I installed such a hydrant outside our garage. If it now needed repair, I wouldn't want to have to dig it up now by hand, I'd want to bring in an excavator to do it. That rental alone could be a big chunk of the quote you're looking at. BTW, I did refurbish the seal on our hydrant last year as suggested above. Not a hard job at all.

If your existing hydrant can't be refurbished, you should be able to buy a high quality yard hydrant for about $100. Hire a local teenager to dig down to where the old one is connected and you're 90% of the way done. A handy friend should be able to make the connection. I installed my own several years ago and it was no big deal.

In my area (Long Island, NY), the going rate for plumbers seems to exceed $300/hour. Do you think you could dig down and replace it in 6 hours?

Call a plumber after the hole is dug. First call a handyman to dig the hole.

Actually, with some prodding, I got my husband to educate himself on the possible problem and he read up on adjusting the height/depth of the rod so it is better lined up with the overflow hole. It's all done without digging or doing anything but adjusting that rod at the top. He worked on that and It appeared to work! The pump isn't going on and off now and we read online about how you can fill a glass of water and hold the hydrant nozzle under the water right when you turn it off, and it should suck some of the water back down the hydrant. I tried that and it worked! So.........we'll see how this goes. Thanks for all your input.