Pumped hydro scales awesomely and is relatively low maintenance, but it has a fairly low energy density, wikipedia quotes 272Wh for 1m^3 at 100m (~30 floors). That's 0.272Wh/kg. You either need tremendous amounts of water, significant height, or both.
By comparison, your ultra-basic low-energy-density lead-acid battery pack is 30~40Wh/kg, 100 times the energy density, and a Li-ion is 130~200Wh/kg.
It's fun to throw out numbers for pumped storage. The Ludington pumped storage plant [1] is pretty big at 1.8 gigawatts. At full power, that's 33 million gallons per minute. The reservoir is 27 billion gallons of water (about 100 billion liters).
By comparison, your ultra-basic low-energy-density lead-acid battery pack is 30~40Wh/kg, 100 times the energy density, and a Li-ion is 130~200Wh/kg.