I may or may not have the seepage from the pipe to one of the heads. (I do smell a little coolant once in a blue moon.) I understand this leak happens because it is very easy to damage the o-ring when the pipe is installed at the factory. Also there is just a little steel "claw" (a sort of flange) and one screw that holds each pipe into the heads, and it isn't as secure as a nice 2-bolt flange would be.
Some folks have posted that the best step is to remove the pipe, clean everything well, and just glue it into the head with RTV silicone sealant. I think this is a better long term solution than just changing the o-ring.
All my hose clams were loose from the factory as well, and some had seepage until I tightened them. If you remove the left air filter, and its backing plate, you can see the clamps under the tank with a flashlight (you might have to push some little hoses or wires aside.) Then with a nice long philips screwdriver you can tighten them. There are 5 clamps under the tank, and 2 on the radiator, and one on the waterpump, for a total of 8, plus one tiny wire clamp that holds the overflow hose to the thermostat housing. That has never leaked on mine.
But my water pump gasket did start to seep at around 10,000 miles. I bought a new gasket from Kawasaki & changed it myself. The gasket they sold me looked a little thicker, and the bag it came in said "improved gasket" so I suspect this was a common problem with the original gasket. After taking off the pump cover I realized that RTV would work fine there too, as there's no real clearance issue, and there was no need to spend $10.50 (!) for one small gasket.
One of the waterpump cover bolts (lower rear) also closes the coolant drain hole, and all your coolant will run out here when you remove it. It has a soft aluminum washer under the head that crushes a little and makes a seal. This should probably be replaced when you take off the cover. I just sanded mine smooth, dabbed a bit of RTV on it, and it has never leaked. I now have almost 25,000 miles.
If you drain the coolant, you must lift the tank part way to get to the filler cap.
Don't lift it too high, and don't disconnect the fuel hoses. Just prop the tank up with a wood block, or hang the front of the tank from the mounting tab with a thin rope slung over a rafter (safer), then use a funnel with a hose on it to fill the coolant.