How Virginia tests its beaches
From May through September, the Virginia Department of Health (VDH) runs a single statewide Beach Monitoring Program. Staff collect water samples about once a week at roughly fifty public beach stations along the coast, including the Virginia Beach oceanfront, the Chesapeake Bay shoreline, and Hampton Roads spots like Norfolk's Ocean View and Hampton's Buckroe Beach.
The test looks for enterococci, a group of bacteria that live in the guts of warm-blooded animals. The bacteria are not usually harmful in themselves, but a high count is a signal that other things you would rather not swim in may be present too. VDH compares each sample against a threshold called the Beach Action Value, set at 104 MPN per 100 milliliters. When a sample comes back above that line, VDH posts a swimming advisory for that station.
What a swimming advisory means, and what it does not
An advisory is exactly one thing: the most recent water sample at that station came back with bacteria above the state threshold. In VDH's own words, a swimming advisory is a way to notify the public of a health risk that may be present. It is a recommendation tied to a single sample, not a verdict on the whole beach or the whole summer.
A few things an advisory is not:
- It is not a closure. A closure is rare and is ordered by the State Health Commissioner. An advisory means "not recommended," and it does not by itself prohibit swimming, though some localities have their own ordinances that do.
- It is not permanent. The reading is a snapshot of one sample on one day. VDH keeps sampling, and an advisory is lifted once levels drop back below the threshold.
- It is not a statement that the water is "unsafe" or "contaminated." It means bacteria were above the threshold in the latest sample, nothing more and nothing less.
How to check before you swim
VDH is the source of record. Its swimming advisories and monitored beaches map shows the current status at every station it tests, so it is the first place to look when you are deciding whether to get in.
Testing follows a weekly rhythm, which is worth knowing when you read a result. In Norfolk, Ocean View stations are sampled on Monday with results posted by Tuesday afternoon. Hampton samples Buckroe Beach and its other beaches on Tuesday, with results a couple of days later. So the status you see reflects the last scheduled sample, not the water this exact minute.
To make this easier, our beach pages now show a notice whenever VDH has posted an advisory for that beach's station, right alongside the jellyfish forecast you came for. If VDH has flagged the water, you will see it on the page.
The common-sense rain rule
You do not need a lab to make one good call on your own: be cautious right after heavy rain. When a storm dumps a lot of water, it washes runoff off streets, yards, and storm drains into the bay and rivers, and bacteria levels commonly rise for a day or two afterward. VDH counts major storm events among the reasons an advisory can be issued. If it has poured in the last day or so, especially near a stormwater outfall or a river mouth, it is reasonable to wait a bit before swimming, whether or not an advisory has been posted yet.
How this fits with the jellyfish forecast
Bacteria and jellyfish are two completely independent things about the same water. A day with high sea nettle numbers can have perfectly clean bacteria readings, and a day with a swimming advisory can be jellyfish-free. One never predicts the other. A jellyfish forecast tells you the chance of getting stung; it says nothing about bacteria, and the reverse is just as true.
What our site now does is put both in one place. The daily Virginia jellyfish report ranks sea nettle conditions beach by beach, and the beach pages carry the VDH advisory notice next to it. You can see both signals for spots like Ocean View Beach Park in Norfolk and Buckroe Beach in Hampton before you decide. Swimming in natural water is never fully guaranteed to be safe, so use both readings as a guide, check the flags when you arrive, and make the call that feels right for your group.