I need some advice on installing a yard hydrant on our main water line from our house well. Our main line dead ends outside the house (after a tee into the house to the pressure tank) with a ball valve- it's essentially capped with the ball valve and was put there by the contractor if we wanted to add sprinklers in the future. Our water is softened and I want to put a hydrant on the end of the line for garden irrigation- will just run a hose from the hydrant. I dug up the end of the line and valve (about 36" deep) to add a 12" 3/4" PVC line to a frost free hydrant but after reading a bit here, there appears to be a concern with cross contamination through the weep hole of the freeze-proof hydrant into the main house water supply. I'm not sure how big a risk this really is- the hydrant's in my yard, there may be some dog poop but it's not a feed lot. There were two things I was thinking, one simple, one complex. The simple plan is forget about the freeze proof hydrant and to just add a riser (galvinized?) from the valve underground and put a spigot on it with a vacum backflow preventor on it and then figure a way to winterize it- I don't really need it in the winter. This way there is no weep hole underground. Could I winterize a 4 or 5 foot riser by sucking it out with a shop-vac? The valve is there, so I thought for winter I could just shut it off and suck out the riser. The more complex option would be to use a pressure backflow before the yard hydrant, but this would still need to be winterized. Any thoughts?
Yard Hydrant Cross Contamination?
- Thread starter anojones
- Start date
- Views: 15857
Kays Supply
Veteran Member
In Illinois a double check valve is all that is required for backflow. There is a company that has made a pretty slick model. www.yardhyrantmadeeasy.com I have made a version for myself that works good. The best solution is to run the valved line into the home, put a double check and a valve, then run it back outside. That way you can service the check valve if you need to and the shutoff valve won't be 3' deep when you need it.
JB4310
Super Member
I don't have first hand experience with yard hydrants but I can't see how you could get cross contamination thru the frost free drain. As long as it's drained into a stone trap that would not allow pressure to push back up the hydrants stand pipe.
I now anti siphon is a concern, but that check valve Kays mentioned should take care of that.
I may be all wrong though, like I said I have no experience with those type of yard hydrants.
JB.
I now anti siphon is a concern, but that check valve Kays mentioned should take care of that.
I may be all wrong though, like I said I have no experience with those type of yard hydrants.
JB.
Kays Supply
Veteran Member
When it comes to health and safety concerning drinking water, it is all about not what are the odds, but if it is possible. The situation that the powers that be are protecting from, is a poison like insect spray or antifreeze being washed out and into the gravel bed. If the hydrant is off and the ground water rises, the poison can get into the stand pipe. This can be drawn back into the main if a backsiphon is setup from a break or even a large flow like a fire hydrant being opened. I don't write the rules, I just have to deal with them. After all this has been said, I would be very careful about drinking from a yard hydrant any time. As a matter of fact, in Illinois, you must paint a backflow protected hydrant yellow and mark it non-potable. The only way you can leave it potable is if you pipe the drain down to an open discharge above grade.
Highbeam
Super Member
The idea is that any sort of bugs or poisons can climb into the open weep hole and into the barrel (standpipe) of that hydrant. It is just like a real fire hydrant, you wouldn't want to drink from that. Consider the vertical section of the yard hydrant to be an open hose, funk can live in there.
Unless you regularly loose water pressure, I wouldn't worry about the cross contamination from a yard hydrant coming back into the home system. True, it is possible but only if you lose pressure in the domestic line.
Unless you regularly loose water pressure, I wouldn't worry about the cross contamination from a yard hydrant coming back into the home system. True, it is possible but only if you lose pressure in the domestic line.
Yeah- it seems low risk as long as there is pressure, I'm on a well with a pressure tank. The only reason I can think of for a loss of pressure is going to be a main line leak or break- in which case I'd end up having to shock the well after the repair anyway. I don't plan on using the hydrant as a potable water source, so the concern is really cross contamination back into the house water, not so much the water in the hydrant itself. I'm probably overthinking this- there must be a billion of these around, including in RV parks etc where the risk would be higher. In fact, we have one on our mainline right next to the well-head that was put in when the well was drilled- although I'd like to cap that one as if that one causes trouble I have to shut off the whole line to repair it.
JB4310
Super Member
The big thing I see on all commercial and institutional buildings are the retrofitted anti siphon adaptors on the outside sillcocks. We're on city water, I can't really picture a scenario where a garden hose would allow contamination of the water supply, even if the system lost pressure.
JB.
JB.
Highbeam
Super Member
The scenario is this: The city water system loses pressure for one of many reasons and some yahoo down the hill opens his faucet and drains the line above him. You, being up hill, will see the water drain out of the main towards the downhill yahoo. This will put a suction inside the water main. Now you go outside and seeing the oppotunity for a free septic pumping put your garden hose into your septic tank and open the hose bib. The vacuum in the water main sucks the sewage through your garden hose and into the water main towards the downhill yahoo. Bummer, the main is full of sewage.
The new antisiphon sillcocks are meant to fix this but many of the old style still remain.
A yard hydrant is built exactly like a fire hydrant. Same risk for cross contamination through the weep hole. We put fire hydrants in bad places all the time, even near sewer manholes. Don't worry about the weephole. You can certainly equip your yard hydrant with an antisiphon valve. They sell them with hose bib threads at home depot.
Thanks for all the advice, I'll just install the hydrant and use an anti-siphon on the faucet. I suppose the anti-siphon on the faucet end will stop the hydrant from draining- no air to replace the water in the pipe. Gotta remember to get that off in the winter.
JB4310
Super Member
We've never lost water pressure in fifty years, but I do get it. When I've heard of other municipalities that had a main go, once they get it repaired there is so much crap in there you can't drink it for a certain time. Not Human crap though like from your scenario, I hope.
I think it will still drain out, maybe just a little slower.
The only problem may be that the hydrant spout may not drain and could freeze and break, not sure how they are configured. or if those antisiphon adaptors hold the water inside, I think they would cause there is a spring that needs to be overcome from the pressure.
So you probably would have to take it off in the winter.
Like those frost free sillcocks, I see alot of them broken cause people forget to take the hose off, if the hose has a closed spray handle and can't drain neither can the faucet.
The beauty of that is they don't find out till they run that faucet in the spring and often it breaks behind the wall and unbeknownst to them, pours water in the basement while they are watering the grass.
JB.