Thanet Bathing Water Quality: Beach Ratings and Sewage Alerts

Thanet has an unusually large number of designated bathing waters for a district of its size, which follows from having sea on three sides and a tourist economy built on the sands. Each designated beach is sampled and classified, the results are published, and short-term pollution warnings are issued separately from the annual rating.

Almost nobody who swims here uses either system, which is a shame, because between them they answer the only question that matters before getting in.

The four classifications

Designated bathing waters in England are classified annually into four bands: excellent, good, sufficient and poor. The classification is calculated from samples taken across the bathing season over four bathing seasons rather than from a single reading, which makes it a statement about a beach’s usual condition rather than about today.

Two things follow from that method and both are routinely misread.

A beach rated excellent can still be unsafe on a particular afternoon, because the rating is historical and the pollution is not. And a beach rated poor is not permanently contaminated; the band reflects a pattern of results, and a single bad summer can move a beach down for years afterwards while conditions improve.

Where a beach is classified poor, signage advising against bathing is required. That advice is about the classification rather than about the water on the day.

What triggers a short-term pollution warning

The annual rating is the background. The daily question is answered by short-term pollution forecasting, which is a separate system.

Predictions are issued for beaches where heavy rainfall or a discharge is known to raise bacteriological levels temporarily. The trigger is usually rainfall: the isle’s drainage carries surface water and, at combined sewer overflows, dilute sewage, and heavy rain past a threshold causes releases that would otherwise back up into streets and houses.

The practical rule that follows is the single most useful thing on this page. After heavy or prolonged rain, wait. The advice generally given is to avoid bathing for a day or two after a significant discharge, and the bacteriological load falls quickly with tide and sunlight.

Discharges are now reported far more openly than they were, and near-real-time maps of overflow activity around the coast are published by the water company and by the regulator. Checking one before swimming takes seconds.

Why the isle is particularly exposed

Three local factors combine, and none of them is anybody’s fault.

The chalk aquifer under Thanet drains quickly, and surface water reaches the sea faster here than across clay. That is good for flooding and bad for dilution time.

The bathing waters sit close together, so a single overflow can affect more than one designated beach depending on tide and wind.

And the sea itself moves along the coast rather than straight out. Longshore drift means a discharge at one point is carried past the next bay rather than dispersed offshore, which is why the beach with the problem and the beach with the reading are not always the same beach.

The Foreness Point discharges

Local concern has focused repeatedly on specific outfalls, and Foreness Point on the north coast is the one most often named. Discharge events there have prompted beach closures, public meetings and regulatory attention over a decade.

That history matters for reading current information. A beach with a poor recent record attracts more sampling and more scrutiny, which means more reported incidents, which can make a beach that is being watched closely look worse than one that is not being watched at all. Reported incidents are partly a measure of attention.

It also matters for what to expect. Where an outfall has a history, the sensible assumption after heavy rain is that it has operated, whether or not a notification has appeared yet.

How to check a beach before swimming

Four checks, in order of usefulness on the day.

Has it rained heavily in the past 48 hours? If yes, that is most of the answer, and no notification is needed to justify waiting.

Is there a live discharge notification? The water company publishes near-real-time overflow activity, and the regulator publishes bathing water data including current advice against bathing.

What does the annual classification say? Useful as background rather than as a decision. A beach rated sufficient rather than excellent is not dangerous; it is a beach with more variable results.

Is there signage at the entrance? Where advice against bathing is in force it is posted, and where a beach is lifeguarded in season the lifeguards will know about a current problem before any website does.

What the sampling actually measures

The classification rests on two bacterial indicators: E. coli and intestinal enterococci. Neither is usually the organism that makes somebody ill. They are markers, chosen because they are reliably present wherever faecal contamination is present and because they can be counted cheaply and consistently.

That indirection matters when reading a result. A high count means contamination has reached the water, not that a specific pathogen has been identified, and a low count means the marker was low in that sample at that moment at that spot.

Samples are taken by hand, at a defined point, during the bathing season. A sampler on a Tuesday morning does not know what happened on the Saturday night, and the classification is built from enough samples over enough seasons that individual variation is smoothed out. Smoothing is exactly what makes it useful as a rating and useless as a daily check.

Who is responsible for which part

Three bodies, and the division explains why complaints go to the wrong place.

The environmental regulator designates bathing waters, takes the samples, calculates the classification and publishes the data. It is also the body that enforces against a water company for an unpermitted discharge.

The water company owns the sewerage network and the overflows, is required to report discharge activity, and is the body whose infrastructure decides how often an overflow operates.

The district council manages the beaches themselves: signage, cleaning, lifeguard provision in season, and the environmental health function that receives illness reports.

A complaint about a discharge goes to the regulator and the company. A complaint about signage, litter or a beach’s condition goes to the council. Sending either to the other loses weeks.

The bathing season, and what happens outside it

Sampling runs through a defined bathing season, broadly the warmer months. Outside it there is no routine sampling and no classification updating, which does not mean the water is worse or better. It means nobody is measuring.

Year-round swimming has grown substantially, on this coast as elsewhere, and the people doing it are in the water precisely when the monitoring is not running and when overflow activity is highest because rainfall is highest. That combination is the single largest gap in the current arrangement, and it is worth knowing rather than being alarmed by: the same rainfall rule applies, and in winter it applies more often.

Lifeguard cover follows the season too, and out of season a beach that feels familiar in August is a different proposition.

Blue Flag, Seaside Award and the ratings that are not water quality

Beaches on the isle have carried Blue Flag and Seaside Award status at different times, and they measure different things from the bathing water classification.

A Blue Flag requires excellent bathing water as one criterion among many others covering management, safety, facilities and environmental education. A Seaside Award has a lower water-quality threshold and more emphasis on beach management.

The practical consequence is that a flag flying at a beach entrance is not a statement about today’s water, and the absence of one is not a statement about contamination. Both are annual awards about the operation of a beach.

Illness, and what it looks like

The most common consequence of swimming in contaminated water is gastrointestinal illness within a day or two, and it usually resolves without treatment. Ear, eye and skin infections also occur.

Two groups should be more cautious than the average: young children, who swallow more water and weigh less, and anyone immunocompromised or with an open wound.

Where illness follows a swim, reporting it matters beyond the individual case. Local authority environmental health teams collate reports, and a cluster following a specific date at a specific beach is evidence that sampling alone will not produce.

Beyond bacteria

Water quality is not the only reason to check a beach, and the other hazards on this coast kill more people than the sewage does.

Tides on the isle move fast across flat sand, and cutting off is a real and regular occurrence at more than one of the bays. Rip currents form at the gaps in the chalk reefs. Cold water shock affects strong swimmers in the same way as weak ones and is worst in spring, when the air is warm and the sea has not caught up.

Lifeguarded beaches are lifeguarded only in season and only during posted hours. Outside those, the flags mean nothing and there is nobody watching.

What a storm overflow actually does

The mechanism is worth understanding because it explains why the answer is rain rather than blame.

Much of the older drainage in the isle’s towns is combined: one pipe carries both foul sewage and rainwater from roofs and roads. That was normal Victorian practice and it is expensive to separate now. In dry weather the pipe carries sewage to treatment. In heavy rain the volume rises far beyond what the pipe and the works can handle.

At that point the system has two options. Either it backs up, which means sewage in streets, gardens and ground floors, or it releases the diluted excess at a permitted overflow. The overflows exist precisely to make the first outcome not happen, and they are permitted rather than illegal.

That is the honest engineering position, and it is not an argument that nothing is wrong. Two things are: overflows operating far more often than the permits envisaged, and reporting that until recently made frequency impossible for anybody outside the industry to establish. Both have changed under pressure, and the near-real-time reporting now available is the direct result of that pressure.

For a swimmer none of it changes the practical rule. Heavy rain means the system was probably relieved somewhere upstream, and the sea takes a day or two to clear it.

Frequently asked questions

What do the four bathing water classifications mean?

Excellent, good, sufficient and poor, calculated from samples taken across four bathing seasons. They describe a beach’s usual condition rather than the water on any given day.

Can I swim at a beach rated excellent after heavy rain?

The rating is historical and the rain is not. After heavy or prolonged rainfall, waiting a day or two is the sensible course regardless of the classification.

How do I find out about a live discharge?

The water company publishes near-real-time overflow activity and the regulator publishes bathing water data including any current advice against bathing.

Does a poor rating mean the beach is always contaminated?

No. It reflects a pattern of results over four seasons, and a beach can carry the band for years after conditions have improved.

Should I report illness after swimming?

Yes, to the district council’s environmental health team. Individual reports are how a cluster at a particular beach on a particular date becomes visible, which sampling alone does not achieve.

Are the beaches lifeguarded?

Some are, in season and during posted hours only. Outside those hours the flags carry no meaning and nobody is watching.