i must be blind

We have a 1999 gulfstream sun voyager. We recently got the coach manual for the rig and its time to winterize. I can not find the water drains anywhere. It has the water manifold. I tried tracing the water lines. I crawled underneith for an hour. it can't be this hard, but I give!
i must be blind

It'sn good to see another Gulfstream owner here on the forum. I have the 1993 Tourmaster and just winterized it also. If it's anything like mine - it really turns out very simple. I had a campsite place do the work since I didn't have the time or compressor to do it myself - but believe I shall from now on. Mine consisted of draining tank, draining hot water tank, switching two valves and taking out the filter. They pumped in the antifreeze and then blew the lines and put some in each trap. That's it.

What part of the country do you guys live in? Us - North East Iowa not far from Decorah.