If they are adding an in ground spa for $7500.00 to an existing pool that would be an incredibly LOW price. If you were adding that to your new pool construction that could be an acceptable price. The gunite, controls and permit would likely cost more than the $7500.
I added a heater, spa, jet pump, deck and remote controls to a pool in Pleasanton last year and he was well over $20K. Permit was $1600.00

Do you have a heater?
Are you set up with spa remote controls?
Are you adding a booster pump to run your jets?
What is the spa finish?
How many jets?
Is your builder licensed/insured?

Ken

Here is a link that might be useful: {{!gwi}}

Who's removing & replacing the existing concrete decking? Who is trenching to the equipment? Is the existing equipment adequate?? How is the bather displacement & spillover getting from one vessel to the next? How are you going to control the valving & heater sequencing?

$7,500??? Sounds like a scam!

Adding a spa to an existing pool should be more like $30-40,000 not including any work to be done on the pool when the tie in plumbing, and masonry ins completed.

$7,500 is high??? Have you ever processed permits in San Jose's living hell of a building department?? Thye are trying to pay for that pretty new city hall - at $7,500 your builder is a scham, unlicensed, or is not including something (a lot of somethings!) !

I'm assuming you are talking about a portable spa, right? If so, then yes, $7500 is high for just a portable spa w/o a gazebo.

Last summer we were going to add a spa to our existing pool during our remodel. Our price was $15,000 - $17,000 to add it into the existing pool. Needless to say, no spa, we opted for a waterfall instead:)