I'm filling a pool, and looking to speed up the process. I have two hose bibs, and wonder if I'm really gaining anything (and how much) by using both?

The house is supplied by a 3/4" line. This tees into two 1/2" lines, one going to each hose bib.

I'm thinking that with one hose, I'll get the volume provided by a 1/2" pipe. Adding the second hose will not double the flow, but should only make it as if a single hose was fed by a 3/4" pipe.

Is my intuition correct?

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    I believe you will since 3/4" pipe has about 2x the flow rate of 1/2" pipe. Best to test it out. Time how long it takes to fill a 5 gallon bucket with 1 and then 2 hoses. – OrganicLawnDIY May 8 '14 at 18:07
  • Many places prefer that you call the fire department to get your pool filled, rather than running a hose into it. Local laws and customs will vary, of course. – Ecnerwal May 8 '14 at 18:49
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    Also, depending on how often you'll be doing this, note that your water bills are actually a water bill + sewage bill in one. The sewage bill is actually much higher, and if this water won't ever get to the sewage it might be possible to rent a hydrant meter. e.g. : wsscwater.com/file/CustomerCare/FHMR.pdf – Aaron May 8 '14 at 20:03
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    No hydrants around here. I suppose the fire department just brings marshmallows and hot dogs to fires. – Tester101 May 9 '14 at 0:08
  • @Ecnerwal Are you serious??? :) Do you have any official reference that this is acceptable? I find it hard to believe that I can personally use a service provider funded by tax-payers money to fill my pool. – Markus A. May 9 '14 at 1:28

I would expect more water to flow unless you have extremely low water pressure. You have a 3/4" line and all the water pressure of either a municipal water system or a water pump. Splitting that into two lines will not likely double the flow rate as there is a pressure drop, but it should increase the total flow rate considerably. I would expect it to almost double, but not quite.

This would be easy to test with an empty bucket. Time how long it takes to fill the bucket with one hose on and then with both.

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    Inquiring minds like to know, so testing is fine, but two hoses are certainly not going to slow down the process. Assuming you have enough hose already, I'd just go ahead and use the two. It'll more than likely help, worst case it will not make any difference. Either way will take a long time, I like the suggestions regarding using a hydrant. – bcworkz May 8 '14 at 21:18
  • I have a flow meter on my main water line and adding a second hose went from 6.3gpm to 9.4gpm – bridiver Nov 3 '18 at 13:16

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