MERCER ISLAND, WA - Thirty-thousand square-feet of total living space. Sixty-seven full bathrooms, 68 bedrooms. A combined value of $570 million. These are the King County's most exceptional properties.

There are just 15 homes in the Seattle area that are so grandiose, so extravagant, and so out-of-reach that the King County Assessor has created a special grade for them called "exceptional properties." The homes are owned by the usual suspects: Bill Gates, Paul Allen, Howard Schultz. Some are owned by lesser known but eminently wealthy individuals, and some owners are hidden behind limited liability companies.

King County created the "exceptional" category over 10 years ago so the county could more uniformly evaluated properties so opulent, they don't often get sold. "Exceptional quality homes are a step above and have been identified has being the very best residences in King county. They represent the very best of materials and craftsmanship, and are often one-of-a-kind properties," the assessor's office told Patch.

King County began sending out 2019 tax bills on Feb. 14, and most bills will drop by about 1 percent. It's an appropriate time to tour the county's 15 "exceptional" properties so you can see how your tax bill compares. Keep in mind: tax bills are relative to home value and vary by city. Some cities in King County saw taxes increase in 2019 (including Medina, Bellevue, and Shoreline) and rates decreased in some cities like Seattle and Mercer Island. Here are the homes ranked for least to most expensive:

1631 Roanoke Way, Mercer Island Owner: James P. Edwards

Appraised value: $17,609,000

2019 tax bill: $132,249.43

Tax rate: $7.51 per $1,000 of assessed value

View of Seattle skyline: Average

Square feet of indoor pool: 940 6435 77th Avenue Southeast, Mercer Island Owner: Paul Allen (located next to his three other properties)

Appraised value: $20,420,000

2019 tax bill: $153,343.17

Tax rate: $7.51 per $1,000 of assessed value

Jet ski lift: Yes

Dock square feet: 1,700 120 Lake Washington Boulevard East, Seattle Owner: 120 LWBE LLC

Appraised Value: $20,844,000

2019 tax bill: $173,480.96

Pool area size: 1,150 square-feet 95 Northwest Park Drive and 97 Olympic Drive Northwest, Shoreline (these two houses are next to each other)

Owner: Christopher R Larson

Appraised value: $26,522,000

2019 tax bill (combined): $304,664.84

Tax rate: $11.49 per $1,000 of assessed value

Value of child's playhouse on property: $24,000

Square feet of underground parking: 7,000 3019 60th Avenue Southeast, Mercer Island Owner: AMLA Holdings LLC

Appraised value: $27,780,000

2019 tax bill: $208,628.10

Tax rate: $7.51 per $1,000 of assessed value

Number of tax bill appeals: 6 since 1991 7939 Overlake Drive West, Medina Owner: Nathan Myhrvold, former Microsoft CTO, founder of patent firm Intellectual Ventures, author of "Modernist Cuisine"

Appraised Value: $30,711,000

2019 tax bill: $243,530.74

Lake Washington view: Excellent

Mt. Rainier view: Good 2019 Evergreen Point Road, Medina Owner: Jon A. Shirley

Appraised value: $42,214,000

2019 tax bill: $334,741.78

Tax rate: $7.93 per $1,000 of assessed value

Tram value: $80,000 801 Evergreen Point Road, Medina Owner: Aspen Ventures LLC

Appraised value: $48,499,000

2019 tax bill: $384,577.40

Tax rate: $7.93 per $1,000 of assessed value

Square feet: 24,130

Waterslide: Yes 923 Evergreen Point Road, Medina Owner: Cascade Trust

Appraised value: $79,221,000

2019 tax bill: $628,179.90

Tax rate: $7.93 per $1,000 of assessed value

Year "gate cottage" was last remodeled: 2011 6611, 6451, and 6555 West Mercer Way, Mercer Island (all three of these homes are located next to each other on the west shore of the island)