I visit San Simeon State Park at least once a year, so I've been keeping an eye on this issue. On my last visit, in late March, I carried extra jugs of drinking water. I stayed at Morro Bay State Park the night before going to SS SP, filling and dumping tanks there.
The water supply in Cambria, which also supplies SS SP, is at a critical level due to the drought and to the town's lack of adequate storage facilities.
Here is part of a story from the 9-3-14 issue of the San Luis Obispo Tribune:
"Local parks officials reduced irrigation and cut water availability for personal use in restrooms and other services. Water spigots are turned off and showers are closed at San Simeon State Park Campground, which gets its water from the Cambria CSD.
Restrooms were closed June 1, with services replaced by portable restrooms and hand sanitizers within the campground, other units of Hearst San Simeon State Park and at Hearst Castle and its visitor center.
The leaky Neptune Pool has been emptied and won’t be refilled until the emergency is over.
Through those and other measures, local State Parks officials hope to achieve an 80 percent reduction in water use. In 2013, State Parks’ May-June CSD bill for water was for 334,356 gallons.
During the most recent billing period (May-June 2014), the bill was for 118,184 gallons. (Note: Public restrooms still were open during May.) That’s a 65 percent savings of 216,172 gallons, according to Tom Kidder, district maintenance chief."
I have also seen articles in the local Cambria paper indicating very mixed feelings about tourists, somewhat along the lines of we need the water so let's not let the tourists use any and also issues of tourism being Cambria's main source of income.
I'd say get your water somewhere else and then go and visit this wonderful state park.