The Wave, 30 years old, gets about 100,000 annual visitors.

The Wave, San Diego County's first municipal water park, opened in Vista in 1994. Over the years, the costs to maintain it have ballooned. An assessment finds it will take somewhere between $6,100,000 and $16,800,000 to modernize the five-acre park fully.

Renovation of the facilities, which include a pool, water slides, the FlowRider wave simulator and a lazy river, would take four months to a year.

Water slides are now classified by Cal/OSHA as an amusement ride, forcing annual safety inspections.

As part of Vista's parks master plan, the city is deciding what needs to go and where improvements can be made.

"I look at the Wave as this huge opportunity," said Deputy Mayor Katie Melendez at a recent workshop on the park's needs. Several people have approached her about having evening events for adults at the Wave, she said. New vendors and more programming could help make it a more vibrant space.

The assessment found that 49 percent of Vista residents live within a ten-minute walk of a park, just below the national median of 55 percent.

The FlowRider wave simulator was one of the first installed in the U.S.

The Wave gets about 100,000 annual visitors, according to city staff. But keeping the aging park up to date won't be cheap.

Over the next four-five months the city will conduct surveys to find out what the community wants, undertake a program assessment, plan development, and mapping to see who benefits. 

The assessment so far, conducted by planning firm Next Practice Partners, gave the Wave a "good" rating, despite its disrepair.

The city can't use park funds to repair or replace the pool deck.

Planners said the park is known for having the world's first Flow Rider, and has been a model for others in the southwest. The city has done a good job maintaining it over the years — but now it needs "a significant capital investment."

Major renovations are needed to keep it safe and operable. The report found a mix of code requirements and violations, safety and maintenance concerns, and outdated standards, such as a lack of gender-neutral locker rooms.

What shows the most wear is the pool deck, particularly the lower deck. Several previous renovations have been done, including the water tower in recent years, but areas are in need of refurbishing.

The FlowRider, being one of the first installed in the U.S., with many of its original components, is costly to operate. Estimates for its repair or replacement range from $250,000 to $4 million.

Since the park was built 30 years ago, water slides are now classified by Cal/OSHA as an amusement ride, necessitating annual safety inspections.

City manager John Conley said the city hasn't budgeted to match the level of deterioration of some of the Wave's facilities. The city can't use park funds to repair or replace items.

Earlier this year, he said, the council approved a maintenance program, and will be relying on redevelopment funding for several maintenance projects.

"Some of the Wave improvements are in there. Some of them are not."

The Wave will be brought back to the city at the beginning of next year, to decide if it should be maintained as is, or more fully renovated.