We found 106 public water systems that could serve the same population as Harbor Inn (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Mason City Water Department | Mason City | 28,079 | 6 | 75 |
| Clear Lake Water Department | Clear Lake | 7,777 | 0 | 8 |
| Rockwell Water Supply | Rockwell | 1,039 | 0 | 8 |
| Dot-2 (i-35 Ra 037w Clear Lake) | County of Cerro Gordo | 1,026 | 0 | 0 |
| Dot-2 (i-35 Ra 038e Clear Lake) | County of Cerro Gordo | 1,026 | 0 | 0 |
| Ventura Water Works | Ventura | 720 | 0 | 1 |
| Nanco, Incorporated | County of Cerro Gordo | 530 | 0 | 0 |
| Thornton Water Supply | Thornton | 422 | 0 | 5 |
| Plymouth Water Supply | Plymouth | 388 | 0 | 1 |
| Bell Harbor | Clear Lake | 352 | 0 | 0 |
| Ventura High School | County of Cerro Gordo | 350 | 0 | 0 |
| Pancake Inn | County of Cerro Gordo | 300 | 0 | 0 |
| Meservey Water Supply | Meservey | 256 | 0 | 12 |
| Clear Lake Bakery Inc. | Clear Lake | 225 | 0 | 0 |
| Agape Christian Family Church | Clear Lake | 208 | 0 | 8 |
| Ventura Grade School | County of Cerro Gordo | 200 | 0 | 0 |
| Reel Inn | County of Cerro Gordo | 200 | 0 | 0 |
| The Ritz Club | Clear Lake | 200 | 0 | 0 |
| Mason City Airport | Mason City | 183 | 0 | 0 |
| Swaledale Civic Center | County of Cerro Gordo | 170 | 0 | 0 |
| Swaledale Water Supply | Swaledale | 165 | 0 | 28 |
| P.m. Park Trustees-east | Clear Lake | 152 | 0 | 10 |
| Woerner Oil Co, Inc | County of Cerro Gordo | 150 | 0 | 0 |
| Viking Inn | County of Cerro Gordo | 150 | 0 | 0 |
| Camp At The Wood's | County of Cerro Gordo | 143 | 0 | 0 |
| Lehigh Cement Company Llc | Mason City | 142 | 0 | 14 |
| Kuns Trailer Ranch | County of Cerro Gordo | 140 | 0 | 0 |
| The Market At Oakwood | Clear Lake | 122 | 0 | 0 |
| Mcintosh Woods State Park | County of Cerro Gordo | 120 | 0 | 0 |
| The Rose Bowl | Mason City | 110 | 0 | 0 |
| Luckys Last Resort Campground | Plymouth | 105 | 0 | 0 |
| Deer Valley Lodge | Ventura | 100 | 0 | 0 |
| Vibrations | Mason City | 100 | 0 | 0 |
| R And R Gas And Repair | County of Cerro Gordo | 100 | 0 | 0 |
| Willow Inn Camp Ground | County of Cerro Gordo | 100 | 0 | 0 |
| Redeemer Lutheran Church | County of Cerro Gordo | 100 | 0 | 0 |
| Muskie Lounge & Kaster's Kove | County of Cerro Gordo | 100 | 0 | 0 |
| Nora Springs-rock Falls School | County of Cerro Gordo | 95 | 0 | 0 |
| Four Oaks (mason City) | Mason City | 84 | 0 | 0 |
| Lime Creek Conservation Area | Mason City | 81 | 0 | 0 |
| Bob's 66 | County of Cerro Gordo | 80 | 0 | 0 |
| Venerian Village | County of Cerro Gordo | 80 | 0 | 0 |
| Coffman Carts | Clear Lake | 70 | 0 | 0 |
| Camp At The Woods | Mason City | 69 | 0 | 0 |
| Andrews Prestressed Concrete-plant | County of Cerro Gordo | 67 | 0 | 0 |
| Oakwood Park Water Association | Clear Lake | 66 | 0 | 0 |
| Andrews Prestressed Concrete-office | Clear Lake | 65 | 0 | 0 |
| Mason City Drive-in Theater | Mason City | 64 | 0 | 0 |
| Oakwood Rv Park | Clear Lake | 60 | 0 | 0 |
| Oak Hills Par 30 Golf Course | Clear Lake | 60 | 0 | 0 |
| Pine Creek Golf Course | Mason City | 55 | 0 | 0 |
| Twin Oak Camp Ground | Clear Lake | 54 | 0 | 0 |
| Hanford Community Church | Hanford | 52 | 0 | 0 |
| Wayne Feeds Division | Mason City | 52 | 0 | 0 |
| Buffalo Run Golf Club | Nora Springs | 51 | 0 | 0 |
| Long Beach Mobile Park | Clear Lake | 50 | 0 | 0 |
| Frontier Club&park View Drive- | County of Cerro Gordo | 50 | 0 | 0 |
| Mitchell Transportation Co. | County of Cerro Gordo | 50 | 0 | 0 |
| County Mission Church | County of Cerro Gordo | 50 | 0 | 0 |
| Strnad Park-cerro Gordo Co Con | County of Cerro Gordo | 50 | 0 | 0 |
| Colony Inn | County of Cerro Gordo | 50 | 0 | 0 |
| Mr Shirley Coe | County of Cerro Gordo | 50 | 0 | 0 |
| Rena Lady | County of Cerro Gordo | 50 | 0 | 0 |
| Willow Pointe | Mason City | 50 | 0 | 0 |
| ZIEGLER CAT (MASON CITY) | Mason City | 49 | 0 | 0 |
| Grandview Circle Water Association | Clear Lake | 48 | 0 | 0 |
| Clear Lake Bp Llc | Clear Lake | 42 | 0 | 0 |
| Brakke Implement | Mason City | 40 | 0 | 0 |
| Troika Club | Mason City | 40 | 0 | 0 |
| Ashley Inn Motel | Mason City | 40 | 0 | 0 |
| Robert Ollenburg Well | Clear Lake | 40 | 0 | 0 |
| Ball Breakers | Mason City | 39 | 0 | 0 |
| Mason City Red Power Inc | Mason City | 38 | 0 | 0 |
| Lakeshore Water Association | Clear Lake | 38 | 0 | 0 |
| Northern Trails Aea Preschool | County of Cerro Gordo | 38 | 0 | 0 |
| Rayburn Court For Mobile Homes | Mason City | 36 | 0 | 0 |
| Rock Falls Lounge | Rock Falls | 35 | 0 | 0 |
| Central Heights School | County of Cerro Gordo | 35 | 0 | 0 |
| Buz-in | County of Cerro Gordo | 30 | 0 | 0 |
| Jim Oleson Privately Owned Wel | County of Cerro Gordo | 30 | 0 | 0 |
| Wilkinson Pioneer Park | Rock Falls | 27 | 0 | 0 |
| Linn Grove Park | Mason City | 27 | 0 | 0 |
| Oakridge Homeowners Association | Clear Lake | 26 | 0 | 0 |
| Camp Tanglefoot | Clear Lake | 25 | 0 | 0 |
| Golden Oval Eggs | Mason City | 25 | 0 | 0 |
| Pepsi Cola Bottling Co. | County of Cerro Gordo | 25 | 0 | 0 |
| Diamond Rose Bowl Corporation | County of Cerro Gordo | 25 | 0 | 0 |
| Caravelle Restaurant | County of Cerro Gordo | 25 | 0 | 0 |
| Mason City Motel | County of Cerro Gordo | 25 | 0 | 0 |
| Hawkeye Motel & Worldwide | Mason City | 25 | 0 | 0 |
| United Sugars Corporation | Mason City | 25 | 0 | 0 |
| Strand Pk-cerro Gordo Conserva | County of Cerro Gordo | 25 | 0 | 0 |
| Shell Rock River Green Belt | County of Cerro Gordo | 25 | 0 | 0 |
| Dot-2 (dist2 Mt Lab-masoncity) | County of Cerro Gordo | 25 | 0 | 0 |
| Little Meeting House | County of Cerro Gordo | 25 | 0 | 0 |
| Old Stone United Methodist Church | County of Cerro Gordo | 25 | 0 | 0 |
| The Store | County of Cerro Gordo | 25 | 0 | 0 |
| Kaster Cove | County of Cerro Gordo | 25 | 0 | 0 |
| Lucille's Place | County of Cerro Gordo | 25 | 0 | 0 |
| Regular Baptist Campground | County of Cerro Gordo | 25 | 0 | 0 |
| Grimms-united Methodist Church | County of Cerro Gordo | 25 | 0 | 0 |
| Winnebago River Court | County of Cerro Gordo | 25 | 0 | 0 |
| Clear Lake State Park | County of Cerro Gordo | 25 | 0 | 0 |
| Camp Gaywood Island House Well | County of Cerro Gordo | 25 | 0 | 0 |
| P And M Park Trustees-west | County of Cerro Gordo | 25 | 0 | 0 |
| Dot-2 (eagle Grove Rest Area) | County of Cerro Gordo | 25 | 0 | 0 |