I don't think you are getting contamination from those lines. Do you know what type of pipe is leaving the house going out to the hydrants? Are these frost-proof hydrants or just spigots? You can dig up the one you don't want and cap the pipe underground, but if you don't know where the piping goes underground and if there's a tee, it won't be easy to abandon a whole section of piping. There should be a valve somewhere in the house that cuts this water off. I have seen where water doesn't come from house at all. Where is your water meter?

If you live in an area where it freezes in winter, this is probably the type of hydrant you have:

https://www.supplyhouse.com/Woodford-Y34-3-Model-Y34-3-4-FPT-Non-Freeze-Iowa-Yard-Hydrant-3-Ft-Burial-Depth

There shouldn't be any issue with contamination from an unused line, but it probably would be a good idea to flush it several times a year as a routine.

Thanks Seabornman and forumlaross20. We aren't sure how the pipe is once it leaves the house. I always wondered if it caused contamination. We live out in the country and have a well. We test the water about every 8-10 years and it always has coliform bacteria (not e-coli yet) and we've had to chlorinate the house and those 2 long hydrant pipes every time. It's a drag. Maybe I'll start a different thread about that.

Yes forumulaross.......that's exactly what we have in the ground. We had the one we use a lot out by the barn and garden replaced about 8-10 years ago. I would have expected it to last longer.

Oh, Seabornman, we don't have a water meter......just a well and pump, pressure tank.

If the one that's broken and causes the pump to go off a couple times a day......where is that water leaking to? When it did this another year, we had tons of rain, so I thought the water table rose, but we've hardly had much rain this year. Just wondering where it goes? And unfortunately, I don't think the guy who put this last one in, put any gravel around the bottom.

Thanks again!

The shutoff valve on a hydrant is at the bottom of the vertical pipe. When hydrants start leaking, it usually requires replacement of the rubber sealing plug. A typical repair kit looks like this and is a doable DIY project. I put a rebuild kit into my hydrant this last year.

https://www.lowes.com/pd/ProPlumber-Hydrant-Repair-Kit/50222667?cm_mmc=shp--c--prd--plb--google--lia--142--inlineandwaterdeliveryvalves--50222667-_-0amp;placeholder=null&ds_rl=1286981&gclid=Cj0KCQiAmL-ABhDFARIsAKywVad1i2m4HDuFoWnQpJsLgLhSNiPINGyP2Hyr8_KSFNteH4stIBKC13UaAuJvEALw_wcB&gclsrc=aw.ds

Your plumber probably replaced the whole hydrant because it reduces the chance of callbacks (sometime a repair kit doesn't fix the issue). A side benefit is that it also puts more money in his pocket.

Where does the leaking water go? Well. the beauty of hydrants is that when the shutoff valve closes, the supply water is shut off, but another valve port is uncovered that lets the vertical column of water drain out underground. No water in vertical pipe means no frozen piping! Yes, the base of the hydrant should have been set in a gravel bed for drainage, but it will probably still work, albeit a bit more slowly.

Thanks formulaross20 Sorry it took me awhile to get back. I watched a couple Youtubes on these types of hydrants and it was very informative. The ground is frozen solid now and we've turned off the basement supply to the hydrant. With this crazy weather, we might not be able to get to it for awhile, but fortunately, I won't need it for my garden for quite awhile yet. Thanks again for your input!