First, contact your zoning/permit office and find out their guidelines/regulations about pools and the enclosures needed. 

If older than 5 years,  replace it.Create a removable durock or fire proof enclosure within the closet,  ad a vent grill.

There is also a smaller separated cottage house (1/1) in the back of the property.The public records classify the third room of the main house as storage and the back cottage as enclosure with plumbing.

Depending on what your skills and experience are but generalling yourself or taking over at enclosure are possibilities.

I went to visit a nice hell hole today, there was supposed to be a pool and screen enclosure.

Carport enclosure additionI found the average sqft selling price in the area over the last year was $77.

Houses had no fireplace, vinyl and carpet, no microwave, white appliances, 7-8 windows, flat doors, 3 sides brick, 30" upper cabinets, wilsonart counter tops and fiberglass tub/shower enclosures.

If you're in an area with lots of traffic I would definitely recommend a large magnet for the tailgate / trunk.  

I have lived in over 5 different states and I can honestly say Houston has the best food and best tailgating parties.Thanks.

I think the county may have just did a drive by appraisal and saw the enclosure and just encluded it into the total figures they already had.