# Filling city pool - how fast?
**URL:** https://boards.straightdope.com/t/filling-city-pool-how-fast/661881
**Category:** Factual Questions
**Created:** [June 25, 2013, 4:36pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881 "2013-06-25T16:36:13Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@Obeseus](https://boards.straightdope.com/u/Obeseus)
#### Post date: [June 25, 2013, 4:36pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/1 "2013-06-25T16:36:13Z")
How quickly can a city fill a swimming pool that holds 200,000 gallons? The figures a city employee gave me would indicate they were pumping in 3000 gallons per hour. Is that even possible?
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### Author:  [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)
#### Post date: [June 25, 2013, 4:43pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/2 "2013-06-25T16:43:36Z")
3000 gallons an hour sounds reasonable to be… and it would take a little over 2 1/2 days to fill the pool. Why does that surprise you? There are huge pumps that can move water a lot faster than 3000 gallons an hour…
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### Author:  [@dracoi](https://boards.straightdope.com/u/dracoi)
#### Post date: [June 25, 2013, 4:49pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/3 "2013-06-25T16:49:40Z")
A standard garden hose is about 5-10 gallons per minute or 300-600 gallons per hour.
When I managed apartments, we had a pool that was only 20,000 gallons and when we needed to drain and refill it, we used two garden hoses at once to get the job done in about 6 hours.
To get to 3,000 gph would take take a few garden hoses, but a swimming pool that big would obviously be using something with higher flow. In fact, 3,000 gph isn’t all that much; even my koi pond has a 5,000 gph pump. A single 3" hose can deliver as much as 25,000 gph ([cite](http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml) with lots of other numbers for comparison).
Given that 3000 gph would take almost 3 days (67 hours) to fill a 200,000 gallon pool, I almost wonder if the city employee is wrong about the flow rate.
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### Author:  [@Iggy](https://boards.straightdope.com/u/Iggy)
#### Post date: [June 25, 2013, 4:50pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/4 "2013-06-25T16:50:59Z")
Fire departments sometimes get called upon to fill swimming pools. A 200,000 gallon pool is not so huge.
An Olympic sized pool (50m long, 2 m deep, 10 lanes wide) is about 660,000 US gallons. A deeper section such as a separate diving well adds a lot of volume.
It is certainly possible to pump well in excess of 3000 gal/hour A low capacity fire department pump might only deliver 500 gallons per _ **minute** _. The capacity of the hydrant is often the limiting factor in using higher flow pumps. The local Volunteer Fire Dept where I grew up had pumps up to about 1200gpm.
ETA: At 500 gpm it would still take 6hr 40 min to fill a 200,000 gal pool if you can pump at that rate non-stop.
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### Author:  [@kdeus](https://boards.straightdope.com/u/kdeus)
#### Post date: [June 25, 2013, 5:09pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/5 "2013-06-25T17:09:50Z")
My 355,000 gallon community pool filled from a 4" water line in 8 hours.
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### Author:  [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)
#### Post date: [June 25, 2013, 5:14pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/6 "2013-06-25T17:14:01Z")
When I was in the Coast Guard, there was nothing special about a 250 gpm pump. That could pump 15,000 gallons in an hour. The small ones were 90 gpm. They can pump 5,400 gallons in an hour.
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### Author:  [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)
#### Post date: [June 25, 2013, 5:30pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/7 "2013-06-25T17:30:44Z")
How do they fill swimming pools in Munich?
Mark Spitz.
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### Author:  [@Obeseus](https://boards.straightdope.com/u/Obeseus)
#### Post date: [June 25, 2013, 11:16pm UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/8 "2013-06-25T23:16:33Z")
> [@dolphinboy](#):
>
> 3000 gallons an hour sounds reasonable to be… and it would take a little over 2 1/2 days to fill the pool. Why does that surprise you?
Because it just didn’t sound legit to me. More to the story – the pool has a leaky filtration system. Depending what figures are to be believed, they would have had to pump in a minimum of 2400 gallons per hour to keep it filled.
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### Author:  [@Isilder](https://boards.straightdope.com/u/Isilder)
#### Post date: [June 26, 2013, 12:59am UTC](https://boards.straightdope.com/t/filling-city-pool-how-fast/661881/9 "2013-06-26T00:59:48Z")
News stories… What is the idea of pumping ? Pump from where to where ?
Why wouldn’t the regular town mains by filling the pool ?
The pool is leaking. Maybe the pump is collecting the leaking water and returning it, so as to neutralise the leak.