286 community and non-transient non-community water systems are listed for Delaware in EPA SDWIS. 36 were sampled under UCMR 5; 17 of those had at least one PFAS result at or above the reporting level, and 14 had a highest single result at or above a 2024 EPA limit (PFOA or PFOS 4 ppt, or Hazard Index 1).
Delaware map · Download: systems (CSV) · all results (CSV, gzip)
These are monitoring results collected under EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) at entry points, where treated water enters the distribution system; they are not tap-water samples. They are not compliance determinations: compliance with EPA's 2024 PFAS limits is judged on running annual averages of compliance monitoring, required from 2029, so a single UCMR 5 result at or above a limit is not a violation. “< MRL” means the compound was not quantified at EPA's minimum reporting level; it does not mean zero.
Sampled under UCMR 5 (36)
| System | PWSID | City | Population | Highest PFOA (ppt) | Highest PFOS (ppt) | Highest HI | Highest single result |
|---|---|---|---|---|---|---|---|
| Artesian Northern Sussex Regional | DE0020003 | Newark | 5,511 | 5.7 | <MRL | 0.002 | PFOA 1–3 × its limit |
| Artesian Southern Sussex Regional | DE00A0323 | Newark | 20,145 | <MRL | 4.7 | 0 | PFOS 1–3 × its limit |
| Artesian Water Company | DE0000552 | Newark | 231,114 | 23.1 | 6 | 0.892 | PFOA ≥ 3 × its limit |
| Bayside Pump District (Tui) | DE00A0837 | Dover | 8,400 | <MRL | <MRL | 0 | Other PFAS detected |
| Bethany Bay Pump District | DE0000221 | Dover | 52,684 | <MRL | 6.1 | 0 | PFOS 1–3 × its limit |
| Bethany Beach Water Department | DE0000556 | Bethany Beach | 12,000 | <MRL | <MRL | 0 | No PFAS detected |
| Bridgeville Water Department | DE0000559 | Bridgeville | 6,000 | <MRL | <MRL | 0 | No PFAS detected |
| Camden Pump District | DE0000124 | Dover | 17,208 | <MRL | <MRL | 0 | No PFAS detected |
| Camden Wyoming Sewer And Water Authority | DE0000563 | Camden | 5,000 | <MRL | <MRL | 0 | No PFAS detected |
| Church Creek (Awc) | DE00A0428 | Newark | 9,654 | <MRL | <MRL | 0 | No PFAS detected |
| Delmar Utility Comm (Tn Of Delmar) | DE0000567 | Delmar | 2,027 | <MRL | <MRL | 0 | No PFAS detected |
| Dewey Beach Water Department | DE0000825 | Frankford | 31,000 | 11 | <MRL | 0.352 | PFOA 1–3 × its limit |
| Dover Air Force Base | DE0000579 | Dover | 11,000 | <MRL | <MRL | 0 | No PFAS detected |
| Dover Water Department | DE0000571 | Dover | 39,491 | <MRL | <MRL | 0 | No PFAS detected |
| East Ncc District | DE00A0334 | Dover | 5,538 | <MRL | <MRL | 0 | No PFAS detected |
| Garrison Lake Pump District | DE0000004 | Dover | 17,148 | <MRL | <MRL | 0 | No PFAS detected |
| Georgetown Water Department | DE0000592 | Georgetown | 7,259 | 36 | 14 | 2.504 | PFOA ≥ 3 × its limit |
| Laurel Water Department | DE0000597 | Laurel | 3,984 | <MRL | <MRL | 0 | No PFAS detected |
| Lewes Board Of Public Works | DE0000602 | Lewes | 9,627 | 6.1 | 9.5 | 0.35 | PFOS 1–3 × its limit |
| Long Neck Water Company | DE0000625 | Long Neck | 11,000 | <MRL | <MRL | 0 | No PFAS detected |
| Meadows Pump District | DE0000271 | Dover | 14,538 | <MRL | <MRL | 0 | No PFAS detected |
| Middletown Water Department | DE0000614 | Middletown | 17,700 | <MRL | <MRL | 0 | No PFAS detected |
| Milford Water Department | DE0000616 | Milford | 9,800 | <MRL | <MRL | 0 | No PFAS detected |
| Millsboro Water Department | DE0000622 | Millsboro | 8,568 | <MRL | <MRL | 0 | No PFAS detected |
| Municipal Services Commission | DE0000634 | New Castle | 5,549 | <MRL | <MRL | 0 | Other PFAS detected |
| Newark Water Department | DE0000630 | Newark | 40,000 | 25.3 | 7.5 | 0.553 | PFOA ≥ 3 × its limit |
| North West Pump District | DE00A0347 | Dover | 4,149 | <MRL | <MRL | 0 | No PFAS detected |
| Rehoboth Beach Water Department | DE0000723 | Rehoboth Beach | 25,000 | 14.9 | 6.2 | 0.692 | PFOA ≥ 3 × its limit |
| Rehoboth Pump District (Tui) | DE0000991 | Dover | 81,417 | 4.4 | <MRL | 0.003 | PFOA 1–3 × its limit |
| Seaford Water Department | DE0000246 | Seaford | 6,699 | <MRL | <MRL | 0 | Other PFAS detected |
| Smyrna Water Department | DE0000657 | Smyrna | 11,813 | 9.8 | 6.7 | 0.003 | PFOA 1–3 × its limit |
| Stage Village Mhc | DE0000569 | Dagsboro | 93 | 7.6 | 8.5 | 0.006 | PFOS 1–3 × its limit |
| Sussex Shores Water Company | DE0000557 | Bethany Beach | 12,450 | <MRL | <MRL | 0 | No PFAS detected |
| Swann Keys | DE0000465 | Salisbury | 1,764 | <MRL | <MRL | 0 | No PFAS detected |
| Veolia Water Delaware, Inc | DE0000564 | Wilmington | 100,495 | 24.4 | <MRL | 1.162 | PFOA ≥ 3 × its limit |
| Wilmington Water Department | DE0000663 | Wilmington | 107,976 | 9.9 | <MRL | 0.002 | PFOA 1–3 × its limit |
Not tested under UCMR 5 (250)
UCMR 5 required monitoring by systems serving 3,300 or more people and by a representative sample of smaller systems. The systems below have no UCMR 5 results in EPA's data. Not tested is not the same as not detected: the absence of results says nothing about PFAS in their water.
| System | PWSID | Type | City | Population | Counties |
|---|---|---|---|---|---|
| Acelero Learning Delaware | DE0020095 | NTNCWS | Milton | 70 | Kent County |
| Allen Harim - Dagsboro Hatchery | DE0000499 | NTNCWS | Millsboro | 47 | Sussex County |
| Allen Harim - Pinnacle Processing Plant | DE0000304 | NTNCWS | Millsboro | 225 | Sussex County |
| Allen Harim - Seaford Feed Mill | DE0020108 | NTNCWS | Millsboro | 34 | Sussex County |
| Allen Harim Foods Inc | DE0000298 | NTNCWS | Harbeson | 1,500 | Sussex County |
| Angola Beach Estates | DE0000840 | CWS | Lewes | 1,400 | Sussex County |
| Angola Crest Ii | DE0000999 | CWS | Lewes | 159 | Sussex County |
| Artesian Northern Kent Regional | DE00A0673 | CWS | Newark | 7,014 | Kent County |
| Ascot Landing Subdivision | DE0020148 | CWS | Bear | 338 | New Castle County |
| Avalon Woods Owners Assoc Inc | DE0000885 | CWS | Georgetown | 306 | Sussex County |
| Baltimore Aircoil | DE0000511 | NTNCWS | Milford | 430 | Kent County |
| Barkers Landing | DE00A0440 | CWS | Magnolia | 498 | Kent County |
| Bayshore Mobile Home Park | DE0000252 | CWS | Ocean View | 533 | Sussex County |
| Bayview Improvement Company (Awc) | DE0000553 | CWS | Newark | 214 | New Castle County |
| Baywood Greens | DE00A0425 | CWS | Long Neck | 909 | Sussex County |
| Beach Babies Day Care | DE00A0733 | NTNCWS | Lewes | 123 | Sussex County |
| Bethany Crest Llc | DE0000628 | CWS | Clarksville | 115 | Sussex County |
| Blades, Town Of | DE0000865 | CWS | Blades | 1,400 | Sussex County |
| Blanton'S Manufactured Home Community | DE0000987 | CWS | Felton | 75 | Kent County |
| Blue Heron Estates | DE00A0680 | CWS | Dover | 111 | Sussex County |
| Briarwood Manor Mhp | DE0000438 | CWS | Pittsford | 296 | Sussex County |
| Brick Mill Early Childhood Center | DE0020126 | NTNCWS | Middletown | 360 | New Castle County |
| Bridgeville Mall (Tui) | DE0000155 | CWS | Dover | 550 | Sussex County |
| Bridgeville Pump District | DE0000949 | CWS | Dover | 1,542 | Sussex County |
| Broadkiln Beach Water Company (Tui) | DE0000238 | CWS | Dover | 3,171 | Sussex County |
| Brumbley'S Family Park | DE00A0697 | CWS | Milton | 48 | Sussex County |
| Burtonwood | DE00A0740 | CWS | Newark | 1,503 | Kent County |
| Bylers Store (West Dover) | DE0020074 | NTNCWS | Dover | 601 | Kent County |
| Canterbury Crossing Pump District | DE00A0348 | CWS | Dover | 471 | Kent County |
| Cape Windsor Community Association Inc | DE0000439 | CWS | Selbyville | 600 | Sussex County |
| Captain'S Way | DE0020111 | CWS | Lewes | 102 | Sussex County |
| Carey Estates, Llc | DE0000521 | CWS | Rehoboth Beach | 312 | Sussex County |
| Carpenters Row | DE0000399 | CWS | Hockessin | 60 | New Castle County |
| Cedar Landing | DE00A0424 | CWS | Newark | 357 | Sussex County |
| Cedar Village Llc | DE0000254 | CWS | Rehoboth Beach | 445 | Sussex County |
| Center For The Creative Arts | DE0000167 | NTNCWS | Yorklyn | 115 | New Castle County |
| Central Christian School | DE0000667 | NTNCWS | Dover | 71 | Kent County |
| Central Delaware Christian Academy | DE00A0746 | NTNCWS | Dover | 110 | Kent County |
| Centreville Layton School System I | DE0000067 | NTNCWS | Centerville | 170 | New Castle County |
| Centreville Layton School System Ii | DE0020094 | NTNCWS | Centerville | 47 | New Castle County |
| Cherry Creek Valley | DE0000608 | CWS | Rehoboth Beach | 78 | Sussex County |
| Childrens Secret Garden | DE00A0694 | NTNCWS | Dover | 60 | Kent County |
| Clearbrooke Estates Pump District | DE00A0326 | CWS | Dover | 768 | Sussex County |
| Colonial Estates Mobile Home Park | DE0000267 | CWS | Dover | 165 | Sussex County |
| Cooper Farm Pump District | DE0000118 | CWS | Dover | 261 | Kent County |
| Country Club Village (Tui) | DE00A0679 | CWS | Dover | 192 | Sussex County |
| Country Grove | DE0020020 | CWS | Dover | 426 | Sussex County |
| Country Living Mobile Court | DE0000623 | CWS | Millsboro | 255 | Sussex County |
| Country Rest Home | DE0000275 | CWS | Greenwood | 65 | Sussex County |
| Countryside Estates | DE0000129 | CWS | Smyrna | 50 | Kent County |
| County Seat Gardens | DE0000901 | CWS | Georgetown | 297 | Sussex County |
| Crosswinds Mhp, Llc | DE0001254 | CWS | Pittsville | 210 | Sussex County |
| Crystal Steel Fabricators | DE00A0498 | NTNCWS | Delmar | 40 | Sussex County |
| Dagsboro Water Dept | DE00A0799 | CWS | Dagsboro | 934 | Sussex County |
| Deer Meadows | DE00A0787 | CWS | Newark | 534 | Kent County |
| Delaware City Water Department (Awc) | DE0000566 | CWS | Newark | 2,610 | New Castle County |
| Delaware Correctional Center | DE0000011 | CWS | Newark | 2,000 | New Castle County |
| Delaware Electric Co-Op | DE0000481 | NTNCWS | Greenwood | 130 | Sussex County |
| Delaware State Fair | DE0000595 | NTNCWS | Harrington | 2,952 | Kent County |
| Delaware State Fire School | DE0000818 | NTNCWS | Dover | 228 | Kent County |
| Delaware Turnpike Administration | DE0000470 | NTNCWS | Newark | 80 | New Castle County |
| Discovery Cove Learning Center | DE0000223 | NTNCWS | Laurel | 55 | Sussex County |
| Dove Estates | DE0000112 | CWS | Ridgely | 111 | Sussex County |
| Dove Run | DE0020124 | CWS | Middletown | 909 | New Castle County |
| Dove Run Shopping Center | DE0020127 | NTNCWS | Middletown | 855 | New Castle County |
| Dover Air Park | DE0000573 | CWS | Dover | 252 | Kent County |
| Drawyers Creek Pump District | DE00A0353 | CWS | Dover | 204 | New Castle County |
| Eagles Nest Fellowship Church | DE00A0527 | NTNCWS | Milton | 400 | Sussex County |
| Eds Mobile Home Park | DE0000615 | CWS | Nassau | 66 | Sussex County |
| Emergency Operations Center | DE00A0648 | NTNCWS | Dover | 200 | New Castle County |
| Enchanted Acres Mhc Llc | DE0000259 | CWS | Crofton | 225 | Sussex County |
| Epworth Christian School | DE0000984 | NTNCWS | Laurel | 400 | Sussex County |
| Evelyn Morris Elementary School | DE0000285 | NTNCWS | Lincoln | 780 | Sussex County |
| Evergreen Post Acute | DE0000841 | CWS | Smyrna | 256 | Kent County |
| Felton Water Department | DE0000580 | CWS | Felton | 1,591 | Kent County |
| Fieldstone Golf Club | DE0020045 | NTNCWS | Greenville | 124 | New Castle County |
| First Step Preschool | DE00A0415 | NTNCWS | Lincoln | 50 | Sussex County |
| Fish Hook Mobile Home Park | DE0000260 | CWS | Georgetown | 72 | Sussex County |
| Fishermans Village (Tui) | DE0000309 | CWS | Dover | 129 | Kent County |
| Flying Dutchman Mobile Home Park 2 | DE0002581 | CWS | Felton | 60 | Kent County |
| Flying Dutchman Mobile Home Park 3 | DE0003581 | CWS | Felton | 81 | Kent County |
| Forest Grove Pump District | DE0000960 | CWS | Dover | 330 | Kent County |
| Forest Park | DE0000590 | CWS | Millsboro | 25 | Sussex County |
| Fox Pointe Subdivision | DE00A0696 | CWS | Smyrna | 500 | Kent County |
| Frederica Pump District | DE0020007 | CWS | Dover | 861 | Kent County |
| Frederica Water Department | DE0000587 | CWS | Frederica | 1,100 | Kent County |
| Frederick Lodge Pump District | DE0000007 | CWS | Dover | 204 | New Castle County |
| Friendship Creek | DE0020119 | CWS | Newark | 366 | Sussex County |
| Gander Woods Pump District | DE00A0770 | CWS | Dover | 42 | Sussex County |
| Glasgow Pines Ii | DE0020138 | CWS | Bear | 235 | New Castle County |
| Granada Mobile Home Court | DE0000611 | CWS | Magnolia | 138 | Kent County |
| Grants Way Pump District | DE00A0522 | CWS | Dover | 639 | Sussex County |
| Greater Ellendale Water District | DE0020112 | CWS | Frankford | 350 | Sussex County |
| Green Acres Pump District | DE00A0327 | CWS | Dover | 213 | Sussex County |
| Greenwood Country Retirement | DE0002275 | CWS | Greenwood | 50 | Kent County, Sussex County |
| Greenwood Life Community | DE0020120 | CWS | Greenwood | 100 | Sussex County |
| Greenwood Mennonite School | DE0000282 | NTNCWS | Greenwood | 350 | Sussex County |
| Greenwood Water Department | DE0000558 | CWS | Greenwood | 973 | Sussex County |
| Hanover Foods Corporation | DE0000230 | NTNCWS | Clayton | 217 | Kent County |
| Happy Place 5, Llc | DE00A0808 | NTNCWS | Middletown | 103 | New Castle County |
| Harrington Water Department | DE0000126 | CWS | Harrington | 3,562 | Kent County |
| Hartly Elementary School | DE0000136 | NTNCWS | Dover | 375 | Kent County |
| Hartly Learning Academy Inc | DE0020056 | NTNCWS | Hartly | 60 | Kent County |
| Hartly Mobile Home Park | DE0000468 | CWS | Camden-Wyoming | 90 | Kent County |
| Hedgerow Hollow | DE0000660 | CWS | New York | 147 | Kent County |
| Henlopen Acres, Town Of | DE0000251 | CWS | Henlopen Acres | 522 | Sussex County |
| Hertrich | DE0020015 | NTNCWS | Milford | 100 | Kent County |
| Hilltop Trailer Park | DE0000560 | CWS | Denton | 65 | Kent County |
| Hocker'S Super Center | DE00A0534 | NTNCWS | Ocean View | 75 | Sussex County |
| Holiday Acres, Llc | DE0000523 | CWS | Rehoboth | 132 | Sussex County |
| Holly Hill Estates | DE0000939 | CWS | Smyrna | 831 | Kent County |
| Holly Oak Mobile Home Park | DE0000568 | CWS | Delmar | 210 | Sussex County |
| Holly View Mobile Home Park | DE0000226 | CWS | Pittsford | 207 | Sussex County |
| Home Town Village Of Cool Branch | DE00A0377 | CWS | Seaford | 654 | Sussex County |
| Homestead Park | DE0000264 | CWS | Pittsford | 230 | Sussex County |
| Hunter Mill Estates Pump District | DE0000220 | CWS | Dover | 432 | Sussex County |
| Hunters Pointe Pump District | DE0000104 | CWS | Dover | 261 | Kent County |
| Hunters Run | DE0020139 | CWS | Bear | 683 | New Castle County |
| Hy-Point Dairy Farms | DE0000916 | NTNCWS | Wilmington | 43 | New Castle County |
| Indian River Acres Pump District | DE0000227 | CWS | Dover | 300 | Sussex County |
| Ingram Village (Awc) | DE0020052 | CWS | Newark | 498 | Sussex County |
| Ingrams Point (Awc) | DE0020103 | CWS | Newark | 87 | Sussex County |
| Inv Performance Materials, Llc | DE0000296 | NTNCWS | Seaford | 135 | Sussex County |
| J & J Mhp | DE0000133 | CWS | Smyrna | 84 | Kent County |
| Kent Co Regional Wastewater Facility | DE0000870 | NTNCWS | Milford | 39 | Kent County |
| Kent Co. Regional Sports Complex - Sys 2 | DE0020116 | NTNCWS | Frederica | 45 | Kent County |
| Kent County Motor Sales | DE0000074 | NTNCWS | Dover | 45 | Kent County |
| Kenton Pump District | DE00A0868 | CWS | Dover | 465 | Kent County |
| Kiddie Academy Of Middletown | DE0020125 | NTNCWS | Fort Worth | 110 | New Castle County |
| Kingdom Kid'S Day Care | DE0020115 | NTNCWS | Hartly | 83 | Kent County |
| Kingsmill | DE0020140 | CWS | Bear | 381 | New Castle County |
| Kitts Hummock Improvement Assoc | DE0000545 | CWS | Dover | 305 | Kent County |
| Kristins Care And Learning Center | DE00A0775 | NTNCWS | Milton | 31 | Sussex County |
| Lakeland/Beechwood Pump District | DE0000546 | CWS | Dover | 459 | Kent County |
| Lakeside Home Llc | DE0000650 | CWS | Cherry Hill | 50 | Sussex County |
| Laurel Pump District | DE00A0575 | CWS | Dover | 81 | Sussex County |
| Laurel Village Mhc | DE0000265 | CWS | Laurel | 918 | Sussex County |
| Law Mobile Home Park | DE0000561 | CWS | Camden | 50 | Kent County |
| Lighthouse Point And Community Center | DE00A0781 | NTNCWS | Millsboro | 36 | Sussex County |
| Little Einstein'S Preschool & School Age | DE0020109 | NTNCWS | Georgetown | 79 | Sussex County |
| Little Einstein'S School Age Center | DE00A0394 | NTNCWS | Georgetown | 33 | Sussex County |
| Long Farm Estates Pump District | DE00A0411 | CWS | Dover | 123 | Kent County |
| Long Neck Village | DE00A0188 | CWS | Millsboro | 345 | Sussex County |
| Lotus Blossom Learning Center | DE0020067 | NTNCWS | Lewes | 40 | Sussex County |
| Love Creek Mhc | DE0000606 | CWS | Laurel | 210 | Sussex County |
| Lullaby Learning Center, Inc. | DE0020092 | NTNCWS | Harbeson | 65 | Sussex County |
| Magnolia Water Department | DE0000610 | CWS | Magnolia | 289 | Kent County |
| Mallard Lakes | DE00A0169 | CWS | Selbyville | 1,500 | Sussex County |
| Mamie A Warren Center | DE0000958 | NTNCWS | Smyrna | 120 | Kent County |
| Maranatha Court | DE0000574 | CWS | Smyrna | 54 | Kent County |
| Meadows At Cubbage Pond | DE00A0212 | CWS | Dover | 201 | Sussex County |
| Meridian Crossing Apartments | DE0020149 | CWS | Bear | 220 | New Castle County |
| Messick'S Mhc Llc System 2 | DE0020062 | CWS | Harrington | 36 | Kent County |
| Messick'S Mhc Llc System 3 | DE0020063 | CWS | Harrington | 45 | Kent County |
| Messick'S Mhc Llc System 4 | DE0020064 | CWS | Harrington | 72 | Kent County |
| Messick'S Mhc Llc System 5 | DE0020065 | CWS | Harrington | 97 | Kent County |
| Messick'S Mhc Llc System 6 | DE0020066 | CWS | Harrington | 63 | Kent County |
| Mid-Atlantic Family Practice | DE0020073 | NTNCWS | Lewes | 140 | Sussex County |
| Milton Cheer Inc. | DE0020076 | NTNCWS | Georgetown | 35 | Sussex County |
| Milton Water Department | DE0000629 | CWS | Milton | 3,200 | Sussex County |
| Misty Pines Pump District | DE00A0420 | CWS | Dover | 168 | Kent County |
| Mobile Gardens I | DE0000651 | CWS | Pittsford | 476 | Sussex County |
| Mother Goose Children'S Center | DE0000544 | NTNCWS | Millsboro | 70 | Sussex County |
| Mountaire Farms Corporate Office | DE0020098 | NTNCWS | Millsboro | 175 | Sussex County |
| Mountaire-Millsboro | DE0001303 | NTNCWS | Millsboro | 1,200 | Sussex County |
| Mt Cuba Center | DE00A0681 | NTNCWS | Hockessin | 60 | New Castle County |
| Mt Pleasant Mhp, Llc | DE0000008 | CWS | Bear | 117 | New Castle County |
| New Market Village | DE0000269 | CWS | Dover | 321 | Sussex County |
| Northside Professional Center | DE0020054 | NTNCWS | Millsboro | 35 | Sussex County |
| O A Newton And Sons Inc | DE0001493 | NTNCWS | Bridgeville | 75 | Sussex County |
| Oak Grove Estates | DE0000548 | CWS | Dover | 150 | Kent County |
| Ollies Imagination Station | DE00A0233 | NTNCWS | Seaford | 60 | Sussex County |
| Paradise Estates | DE00A1745 | CWS | Newark | 126 | Kent County |
| Parkside | DE0020123 | CWS | Middletown | 1,467 | New Castle County |
| Peaceful Child, Llc | DE0020133 | NTNCWS | Lewes | 50 | Sussex County |
| Peddlers Village Shopping Center | DE0000001 | NTNCWS | Wilmington | 165 | Sussex County |
| Pepper Creek District (Tui) | DE0020021 | CWS | Dover | 414 | Sussex County |
| Pepper Ridge Park | DE0000464 | CWS | Selbyville | 209 | Sussex County |
| Perdue Feed Mill | DE00A0341 | NTNCWS | Salisbury | 47 | Sussex County |
| Perdue Foods Llc | DE0000833 | NTNCWS | Georgetown | 1,500 | Sussex County |
| Pine Ridge Mobile Home Park | DE0000270 | CWS | Seaford | 222 | Sussex County |
| Pine Valley Mobile Home Park | DE0000644 | CWS | Rehoboth Beach | 145 | Sussex County |
| Pinewood Acres | DE0000547 | CWS | Dover | 1,200 | Kent County |
| Pleasant Acres, Llc | DE0000430 | CWS | Millsboro | 60 | Sussex County |
| Point Farm | DE00A0379 | CWS | Dover | 270 | Sussex County |
| Ponds Of Odessa (Awc) | DE0020088 | CWS | Newark | 216 | New Castle County |
| Ponds Of Willow Grove | DE0020022 | CWS | Dover | 126 | Kent County |
| Quillens Point | DE0000924 | CWS | Ocean View | 150 | Sussex County |
| Rehoboth Bay Community | DE0000645 | CWS | Rehoboth Beach | 1,575 | Sussex County |
| Rise & Shine Learning Center | DE00A0693 | NTNCWS | Frankford | 150 | Sussex County |
| Sand Hill Acres | DE0000115 | CWS | Laurel | 384 | Sussex County |
| Sand Hill Mobile Home Park | DE0000982 | CWS | Rehoboth Beach | 120 | Sussex County |
| Sandy Ridge Pump District | DE00A0699 | CWS | Dover | 243 | Sussex County |
| Scottsdale Mobile Home Park | DE0000599 | CWS | Pittsford | 300 | Sussex County |
| Sea Winds Pump District | DE00A0516 | CWS | Dover | 141 | Sussex County |
| Seaglass At Rehoboth Beach | DE0020117 | CWS | Rehoboth Beach | 674 | Sussex County |
| Selbyville Water Department | DE0000654 | CWS | Selbyville | 3,502 | Sussex County |
| Serenity Manor Estates | DE0000121 | CWS | Wyoming | 110 | Kent County |
| Shady Acres Mobile Home Park | DE0000600 | CWS | Dover | 152 | Sussex County |
| Shady Oak Trailer Court | DE0000272 | CWS | Georgetown | 108 | Sussex County |
| Shawns Hideaway System #1 | DE0001646 | CWS | Millsboro | 341 | Sussex County |
| Shell'S Early Learning Center-Harrington | DE00A0710 | NTNCWS | Harrington | 83 | Kent County |
| Siemens Healthcare Diagnostics | DE0000814 | NTNCWS | Newark | 1,500 | New Castle County |
| Silver View Farm | DE0000641 | CWS | Rehoboth | 398 | Sussex County |
| Skateworld, Inc. | DE0020087 | NTNCWS | Laurel | 60 | Sussex County |
| Slaughter Beach Pws | DE0002618 | CWS | Newark | 858 | Sussex County |
| South East Pump District | DE00A0376 | CWS | Dover | 951 | New Castle County |
| South Shores (Tui) | DE00A0404 | CWS | Dover | 402 | Sussex County |
| Southwood Acres Pump District | DE0000613 | CWS | Dover | 591 | Kent County |
| St Andrews Apartment New Addition | DE0020137 | CWS | Bear | 272 | New Castle County |
| St Andrews Apartments | DE0020144 | CWS | Bear | 360 | New Castle County |
| St Andrews School I | DE0000023 | NTNCWS | Middletown | 200 | New Castle County |
| St Andrews School Ii | DE0002023 | NTNCWS | Middletown | 140 | New Castle County |
| St Andrews Single Family Homes | DE0020143 | CWS | Bear | 120 | New Castle County |
| Stockley Center | DE0000276 | CWS | Newark | 749 | Sussex County |
| Stockley Regional | DE0020131 | NTNCWS | Newark | 2,861 | Sussex County |
| Strimel'S Mhp Llc. | DE0000492 | CWS | Dover | 40 | Kent County |
| Summit Aviation | DE0000109 | NTNCWS | Middletown | 50 | New Castle County |
| Summit Pond Pump District | DE0000140 | CWS | Dover | 177 | New Castle County |
| Sussex Academy Elementary School | DE00A0685 | NTNCWS | Georgetown | 138 | Sussex County |
| Sussex County Industrial Airpark | DE0000537 | NTNCWS | Frankford | 450 | Sussex County |
| Sussex Manor Mobile Home Park | DE0000442 | CWS | Southfield | 195 | Sussex County |
| Sussex Technical School District | DE0000291 | NTNCWS | Georgetown | 1,800 | Sussex County |
| Sycamore Chase (Awc) | DE0020121 | CWS | Newark | 291 | Sussex County |
| Tall Pines Resort Community Sys1 | DE0001605 | CWS | Lewes | 538 | Sussex County |
| Tall Pines Resort Community Sys2 | DE0002605 | CWS | Lewes | 53 | Sussex County |
| Teal Point (Tui) | DE00A0321 | CWS | Dover | 117 | Sussex County |
| The Little Campus, Llc | DE0000955 | NTNCWS | Newark | 134 | New Castle County |
| The Next Step Learning Center Gumboro | DE00A0774 | NTNCWS | Millsboro | 115 | Sussex County |
| The Vines Of Sandhill (Awc) | DE0020099 | CWS | Newark | 336 | Sussex County |
| Todds Mobile Court | DE0000253 | CWS | Seaford | 189 | Sussex County |
| Twin Maples Trailer Park | DE0000596 | CWS | Monroeville | 123 | Kent County |
| United Parcel Services | DE0000484 | NTNCWS | Baltimore | 112 | Kent County |
| University De Carvel Research & Ed Cntr | DE0020006 | NTNCWS | Georgetown | 60 | Sussex County |
| Upcountry Manufactured Home Community | DE0000102 | CWS | New York | 65 | Sussex County |
| Village Of Grandview | DE0000572 | CWS | Dover | 108 | Kent County |
| Village Square Academy Learning Center | DE0000019 | NTNCWS | Ocean View | 50 | Sussex County |
| Villagebrook | DE0020141 | CWS | Bear | 847 | New Castle County |
| Voshells Cove Pump District | DE0000125 | CWS | Dover | 267 | Kent County |
| White Oak Subdivision | DE0000888 | CWS | Hartly | 30 | Kent County |
| Wild Quail Pump District | DE00A0159 | CWS | Dover | 1,017 | Kent County |
| Willow Grove Mill | DE0020122 | CWS | Middletown | 3,090 | New Castle County |
| Willow Lake Pump District | DE00A0757 | CWS | Dover | 129 | Sussex County |
| Willow Tree Properties Llc | DE0000134 | CWS | Dover | 123 | Kent County |
| Wilmington Vamc | DE0020057 | NTNCWS | Wilmington | 1,695 | New Castle County |
| Winterthur | DE0000503 | CWS | Winterthur | 687 | New Castle County |
| Woodbridge High School | DE0020068 | NTNCWS | Bridgeville | 675 | Sussex County |
| Woodland Trailer Court | DE0000661 | CWS | Smyrna | 41 | Kent County |
| Woodlands Of Millsboro Pump District | DE00A0279 | CWS | Dover | 177 | Sussex County |
| Woods Edge Mobile Home Park | DE0000549 | CWS | Monroeville | 45 | Kent County |