So I bought this blow-up bouncy waterslide thing for my yard, because I am trying to secure a place in my nieces’ hearts forever. So far it’s a hit!
The kids played with it for several hours even though the water was cold as heck. I gave them all I could give them from my 40gal water heater but that only lasts so long.
I read a comment on Amazon that someone left, saying they bought a pond pump to suck water from the pool at the bottom of the slides and send back up to the sprinklers up top. The sun warms the water - no more blue-lipped kids!
I don’t know anything about pumps, though. I know I need something that is abso-fucking-lutely waterproof, will not electrocute the children, move water horizontally about 6’ and vertically about 8-9’, and give pressure at least near that of a residential water line (it can be less). And also will not electrocute the children.
I’ve seen some of you folks discuss psi and pumps like some of us discuss albums and movies. So please, find me a pump 
I don’t know how much water you need to flow, but a marine bilge pump might do the trick, running off of a 12V battery. Take a look here: Bilge Pump Systems
Try a pool cover pump, like this one.
They are designed to be attached to a garden hose and run submerged for hours or even days. The good ones can run dry without major damage.
I have had one like that in the link for fifteen years, and it still works fine.
ETA: I would hesitate to use line voltage in water that had children in it though. Make sure there is a GFCI involved.
A boat bilge pump should work. Just wanna say that Aunt JJ rocks!!
I would have to agree, for the electrical issue.
That little pool cover pump does 1200gph with a wide hose, but it uses line voltage.
Maybe a bilge pump hooked up to a DC power supply?
Something like this may work. The attachment goes in the water, the pump and electrical connections can stay well away. I have a similar one tha I got at Home Depot, but can’t remember the brand. I’ve been using it for over 5 years.
Providing pressure like you’d see from the house poses the largest limitation. That gets expensive. Most the pumps your looking at are single stage centerfugal pumps, they can’t make much in the way of pressure, they provide volume.
Pumps that can make pressure don’t generally fall in the cheap price range. There is also the matter of balancing pressure vs to much pressure.
I’d try a cheapo 1/3 hp submersible and adapt the output to a hose fitting. It’s not household pressure but it will likely meet your needs. They can’t make enough pressure to damage anything and as long as they are in water won’t burn themselves up. They are also completely waterproof, just keep the plug out of the water.