Outside garden hose bib plumbing - 1/2" or 3/4"'pex

Question

I recently renovated and I now want to setup an outside garden hose. I can either hook it up to the 1/2" PEX or the 3/4" PEX. I have 3/4" PEX coming from main water entry to my water heater, then from there the whole house is on 1/2". (Side story, my water pressure / flow is not that great throughout.

Should I hook up my outside garden hose to the 1/2" PEX (that's basically feeding my kitchen) or setup a new new 3/4" PEX from my water heater (not talking about getting hot water out, just the layout)?

I guess this ties in the conversation, I currently bought a 3/4" hose, but if a 1/2" hose is recommended, I can do that also.

I don't have a big yard (25' * 25'), water source is for washing car and light gardening.

Open to advice!

PS: Saw this related post : routing hoses in the duff, 5/8" garden hose, or 3/4" garden hose, or 3/4" polyethylene? but still not sure.

PPS: Also open to advice on the 1/2" PEX, should I have had this done in 3/4" PEX?

Answer 1

I think you should take off for the outside faucet from the 3/4" PEX. This will have a lesser effect on the water pressure inside the house than taking off on the 1/2" line that goes to the kitchen. You can always throttle back at the outside faucet if you need to.

EDIT You could run a 1/2" line to the outside faucet, split off from the 3/4" PEX.

Answer 2

1/2" is fine for individual fixtures such as sinks and dishwashers, but high flow fancy showers should be 3/4" Also, your trunk line should have been 3/4". It also depends upon the water pressure supplied by your utility or well. If it's high enough, you can "get by" with 1/2" but bigger is usually better. The only disadvantage of 3/4" on a the hot pipe is that it takes longer to get hot water at a remote faucet due to the increased volume of water that needs to be moved. Re-circ systems fix that, though.

I think you already answered your own question regarding your outdoor faucet. I would suggest running 1/2" to the location near the water heater and not continue to overload your existing plumbing. 1/2" is plenty for just one faucet.

Answer 3

Pressure loss in a pipe is proportional to the flow through the pipe. A garden hose has potential for high flow, meaning higher pressure loss in the pipe, and you mention that the system pressure is already "not that great."

I can think of two reasons not to use a larger-than-necessary pipe: when it simply costs too much to use the oversize pipe (usually because it's a long run), or when you'll have to wait a while for the water in the pipe to be flushed out (as when waiting for hot water to flow from a centrally-located heater to a distant fixture). Probably neither of these applies here.

Just as nobody ever comes back to DIY.se and says "I wish my circuit breaker panel didn't have so many open spaces for later use," I also believe nobody would say, for a situation like the one you described, "I wish I'd used a smaller pipe."