
Delaware Beach Water Quality
What Delaware Department of Natural Resources and Environmental Control monitors at Delaware beaches, how much of the coast that covers, and where it publishes today's advisory status.
EPA's 2025 record: 22 of 22 Delaware beaches were sampled for bacteriaDelaware in EPA’s 2025 swimming season report
Last verified season, not todayDelaware enrols and samples nearly every beach EPA counts. Every figure here is EPA’s, from the 2025 season as its database stood on September 02, 2026. It describes last season’s monitoring rather than today’s status, and none of it says any water is safe.
Where Delaware publishes current advisories
Delaware is one of the few programmes that publishes its own caution about how to read its numbers, and it is the caution this whole vertical is built around: DNREC says its sampling results are guidance about water quality rather than an indicator of whether it is safe or unsafe to swim at a specific moment. All 22 of the state’s BEACH Act beaches are monitored program beaches. DNREC also distinguishes its ocean beaches from the Inland Bays, where it says water quality varies more.
For the record, EPA’s BEACON jurisdiction page lists Delaware Dept Natural Resources & Environmental Control as the Delaware beach program agency, with its own stored link. EPA’s stored links are not always current; the advisory link above is the verified one. EPA BEACON jurisdiction detail for Delaware
EPA’s three counts for Delaware Enrolled and sampled
EPA keeps a national list of beaches and sorts them three ways: every BEACH Act beach it counts, the subset in a reporting programme, and the subset of those that a monitoring programme actually sampled at least once during the season. The distance between the first and the last is the useful number, and in Delaware it is 0 beaches.
- 22 BEACH Act beaches
- 22 program beaches (100%)
- 22 sampled at least once (100% of program)
EPA BEACON, 2025 swimming season, as the database stood on September 02, 2026. EPA’s counts and EPA’s definitions.
Delaware is one of 16 states that both enrol and sample nearly every beach EPA counts, which is the strongest position on this measure. It still says nothing about any particular day: sampling frequency varies from twice a week to once a fortnight depending on the site, and a beach sampled on Monday is unsampled on Thursday.
US EPA, Find Information about a Particular U.S. Beach“This National List of Beaches provides information whether a beach that is included in a water quality monitoring and public notification program is monitored or not, or if it is not part of the program (those are shown as “Tier 4” in the list).”
The Delaware monitoring season
Delaware Department of Natural Resources and Environmental Control publishes a monitoring season for Delaware: mid May through mid September, which is roughly May 15 to September 15. Today falls outside that window.
Delaware Department of Natural Resources and Environmental Control“From mid-May through mid-September, DNREC samples beaches throughout the state on a weekly, bi-weekly or semi-weekly basis to determine whether bacteria levels exceed thresholds that indicate an elevated risk of illness from swimming or other recreational contact where the head is submerged.”
The consequence matters more than the dates. Outside the season most beaches in the state are not being sampled at all, so an unposted beach in April or November usually means nobody looked rather than that a sample came back under the threshold. That is the same trap as an unmonitored beach in mid-July, arriving by a different route.
How Delaware runs beach monitoring
In Delaware Department of Natural Resources and Environmental Control’s own words, from its own page, with the authorship check shown underneath.
Delaware Department of Natural Resources and Environmental Control“From mid-May through mid-September, DNREC samples beaches throughout the state on a weekly, bi-weekly or semi-weekly basis to determine whether bacteria levels exceed thresholds that indicate an elevated risk of illness from swimming or other recreational contact where the head is submerged.”
The division of labour is the same everywhere and it is worth knowing before you make a phone call. EPA writes the performance criteria and funds the programme, the state runs the sampling and sets the threshold, and in many states the actual posting decision belongs to a county health officer.
US EPA, Beach Grants“The EPA awards grants under authority of the BEACH Act to eligible states, territories and Tribes with beaches on ocean and Great Lakes coasts to develop and implement programs to monitor their beaches and notify the public when it is not safe to swim. During each swimming season, state and local health and environmental protection agencies monitor the quality of water at the nation’s beaches. When bacteria levels in the water are too high, these agencies notify the public by posting warnings or closing the beach.”
US EPA, Find Information about a Particular U.S. Beach“States, Tribes, territories and local governments decide whether to open or close a beach.”
What a Delaware advisory does and does not mean
A posting is triggered by a count of fecal indicator bacteria: enterococci in marine water, Escherichia coli in the Great Lakes and most fresh water. Neither organism is usually the thing that makes people ill. They are counted because sewage and animal waste carry them in enormous numbers, so a high count is evidence that the pathogens that do cause illness are probably present.
US EPA, What Affects Human Health at the Beach“In the event that beaches are closed or advisories are posted, it is most often because water samples for certain bacteria indicate that harmful bacteria, viruses, protozoa, or parasites are likely present in the waters.”
Four things follow. A bacteria posting says nothing about algal toxins, chemicals or rip currents, which are separate programmes. The result is a laboratory result, so it describes water that was in front of somebody about a day earlier. The threshold is a number rather than a cliff, and thresholds differ by state. And the cause is almost always rain, which is why the practical advice is about timing rather than about any particular beach.
US EPA, What Affects Human Health at the Beach“Polluted runoff (water that drains after rainfall) and untreated sewage released into the water can expose swimmers to harmful microorganisms called “pathogens.” These pathogens can be present at or near the site where polluted discharges enter the water.”
US EPA, What Affects Human Health at the Beach“Be aware of any signs indicating the beach is closed or the water is not safe because of bacteria, riptides or other hazards. In areas that are not monitored regularly, choose swimming sites in less developed areas with good water circulation, such as beaches at the ocean. Avoid swimming at beaches where you can see discharge pipes or at urban beaches after a heavy rainfall.”
If you want the shortest useful rule for Delaware or anywhere else: check the state page before you leave, read the sign at the access point when you arrive, stay out for a day or two after heavy rain, keep away from the sand next to a visible outfall or creek mouth, and try not to swallow the water.
US EPA, What Affects Human Health at the Beach“When waterborne pathogens are present, most swimmers are exposed when they swallow the water. You will be less likely to get sick if you wade or swim without putting your head under water.”
US EPA, What Affects Human Health at the Beach“Children, the elderly and people with weakened immune systems are the most likely populations to develop illnesses or infections after coming into contact with polluted water, usually while swimming.”

Delaware against the other 29 BEACH Act states
Ordered by the number of beaches EPA counts. A state with more monitored beaches is not a cleaner state, and a state with a lot of unmonitored beaches may simply have a very long shoreline.
| State | BEACH Act beaches | Program beaches | Sampled | Program miles | Shape |
|---|---|---|---|---|---|
| Washington | 1,228 | 84 | 61 | 51.22 | Most beaches outside the program |
| Michigan | 594 | 580 | 210 | 134.79 | Enrolled, mostly not sampled |
| Massachusetts | 574 | 573 | 572 | 237.46 | Enrolled and sampled |
| Florida | 560 | 232 | 232 | 485.65 | Most beaches outside the program |
| New Jersey | 454 | 211 | 211 | 14.36 | Most beaches outside the program |
| Hawaii | 408 | 408 | 173 | 114.47 | Enrolled, mostly not sampled |
| New York | 354 | 353 | 328 | 134.71 | Enrolled and sampled |
| California | 252 | 248 | 248 | 701.42 | Enrolled and sampled |
| North Carolina | 227 | 225 | 225 | 421.61 | Enrolled and sampled |
| Alaska | 214 | 11 | 11 | 17.69 | Most beaches outside the program |
| Wisconsin | 195 | 117 | 117 | 41.16 | Most beaches outside the program |
| Texas | 168 | 168 | 61 | 153.98 | Enrolled, mostly not sampled |
| Maine | 106 | 66 | 66 | 31.51 | Most beaches outside the program |
| Oregon | 89 | 24 | 24 | 28.51 | Most beaches outside the program |
| Rhode Island | 82 | 67 | 67 | 24.21 | Most beaches outside the program |
| Minnesota | 80 | 38 | 37 | 31.94 | Most beaches outside the program |
| Ohio | 76 | 76 | 76 | 49.44 | Enrolled and sampled |
| Connecticut | 72 | 72 | 71 | 19.02 | Enrolled and sampled |
| Maryland | 59 | 59 | 59 | 31.7 | Enrolled and sampled |
| Illinois | 57 | 56 | 48 | 15.61 | Enrolled and sampled |
| Virginia | 47 | 47 | 47 | 58.15 | Enrolled and sampled |
| Georgia | 38 | 28 | 28 | 37.45 | Most beaches outside the program |
| Alabama | 24 | 24 | 24 | 31.74 | Enrolled and sampled |
| Louisiana | 24 | 23 | 23 | 20.57 | Enrolled and sampled |
| Indiana | 24 | 24 | 24 | 33.14 | Enrolled and sampled |
| Delaware | 22 | 22 | 22 | 29.02 | Enrolled and sampled |
| South Carolina | 21 | 21 | 21 | 105.3 | Enrolled and sampled |
| Mississippi | 21 | 21 | 21 | 46.2 | Enrolled and sampled |
| New Hampshire | 16 | 16 | 16 | 8.76 | Enrolled and sampled |
| Pennsylvania | 13 | 10 | 9 | 2.19 | Most beaches outside the program |
Delaware beach water quality FAQ
More from the Delaware coast
Beach water quality by state
Beach water quality across the country, including the 20 states with no BEACH Act programme and the reason for each.
All counts on this page are reproduced from the EPA BEACON 2.0 Dynamic National Report for the 2025 swimming season as the database stood on September 02, 2026, a US Government work in the public domain. Federal quotations are verbatim from EPA and CDC; state quotations are verbatim from agency public records with the authorship check shown. Current advisory status is published by Delaware Department of Natural Resources and Environmental Control, which issues and lifts the advisories for Delaware.
Hero image: “Coney Island beach on Memorial Day” by David Reilly, CC BY 2.0