Guide

Beach water: bacteria counts and swim advisories

Checked September 28, 2026 against the Texas General Land Office’s Texas Beach Watch program: its website and FAQ, its map layer, its 2025-2026 quality assurance project plan and its press releases.

The beach tile shows what the Texas General Land Office (GLO) publishes through its Texas Beach Watch program: the latest bacteria sample at each beach it samples in the board’s counties. The GLO tests for one thing, Enterococcus bacteria, mostly once a week. This page says what the levels mean, who acts on them, and what a sample cannot tell you.

What the tile shows

The tile reads the GLO’s own map layer, the data behind the interactive map on texasbeachwatch.com. The layer has one row for each sampling station: the beach it belongs to, its county, the level (Low, Medium or High), the Enterococcus count and the date the sample was taken.

• A beach is its stations. The GLO samples most beaches at more than one station; the City of South Padre Island has nine. The tile groups stations under the GLO’s own beach name and shows the beach at its worst station. The line under it gives that station’s count, how many stations the beach has, and the day it was sampled.
• Each beach is filed under the nearest board town. Only beaches in the board’s own counties are listed.
• A beach with no current row in the GLO’s layer shows “No sample listed”, not a green level. A level the tile does not recognise is shown as Check, never as Low.

There are three boards, each covering a stretch of the Gulf coast: Cameron and Willacy counties; Kleberg, Nueces, San Patricio, Aransas, Refugio and Calhoun counties; and Jackson, Matagorda, Brazoria, Galveston, Harris, Chambers and Jefferson counties.

The three levels

The levels are the GLO’s, and so are the words. Counts are in MPN (most probable number) per 100 ml of water.

The 104 line comes from the U.S. Environmental Protection Agency. The GLO says the EPA’s recommended single sample maximum for Enterococcus is 104 per 100 ml, and that “when the counts are above this level, swimming is not recommended.” Medium is not an advisory. The GLO’s own flyer describes its yellow level as a warning “that the water may be dangerous.”

The lowest count the GLO’s method can record is 5 per 100 ml, so a 5 means that little or less. The highest it can measure is 24,196.

What an advisory means, and who posts it

• The GLO recommends it. In the GLO’s words, a water quality advisory is issued “when bacteria levels in the water could cause someone to become sick,” and when Enterococcus levels exceed the EPA’s standard, “a water quality advisory is recommended.” The GLO says it “works with local governments to issue advisories warning the public not to swim in affected waters.”
• Local governments post the signs. The GLO’s sampling plan says that when the limit is exceeded, local government representatives are notified immediately and “may then require signs warning of elevated bacteria levels to be posted.” Its website says local governments post advisory signs provided by the GLO at beach access points, and its FAQ says many local governments “choose to” do so. A High on the tile with no sign at the beach is still a High.
• An advisory is not a closure. “The GLO does not close beaches when a water quality advisory is in effect. Local authorities issue beach closures.” You may still use a beach under an advisory, the GLO says, “as long as local authorities have not closed that beach”; it is the water you are asked to stay out of.

How long an advisory lasts

The GLO’s FAQ says that once a sample is high enough for an advisory, the water at that beach “must be sampled every 24 hours until bacteria levels fall within a safe range,” and that an advisory “lasts at least 24 hours but can be extended if bacteria levels continue to exceed recommended levels.” Its sampling plan says that in practice the resample is taken 24 to 48 hours after the first. On the tile, a beach stays red until the GLO’s layer carries a newer sample from that station below the line.

What Enterococcus tells you, and what it doesn’t

Enterococcus is an indicator, not the thing that makes people ill. The GLO says the bacteria “thrive in water contaminated with sewage or storm water runoff, and scientists often use the bacteria to indicate the presence of harder to detect, disease-causing microorganisms.” It also says Enterococcus comes from “animals with hair, fur, or feathers” and is “a natural part of coastal ecosystems.”

The GLO lists the sources of bacteria in coastal water as sewage treatment plants and septic systems that are not working properly, storm water runoff, boating waste, humans, pets, livestock and wildlife.

It is the only thing the program tests for. The GLO says it “does not test for any other bacteria, including the vulnificus bacteria (flesh eating).” A Low reading says nothing about Vibrio.

The health risk

The health information on the Beach Watch site is taken from the EPA’s national beach guidance. It says the main way people are exposed is contact with polluted water while swimming, including swallowing it by accident. The illness it causes most often is gastroenteritis, with symptoms including chills, nausea, diarrhoea and fever. Infections of the eye, ear, skin and upper respiratory tract can also happen, often when organisms get into small breaks in the skin, or into the ear or nose after diving.

The GLO does not publish a list of who is most at risk. Its sampling plan calls children “an at-risk population” and notes that they spend most of their time in the shallowest water, a foot deep or less. The EPA table the site reproduces lists infections “in immunocompromised individuals” among the effects of one of the bacteria, and death “in susceptible populations” among the effects of another.

A weekly sample is not today’s water

• How often. The GLO collects samples weekly in the peak beach season, March through October, and every two weeks the rest of the year. The one exception is April, when it samples three times to make room for a week of staff training. So there is no off season on this tile.
• When. The GLO’s sampling plan names Monday as the preferred sampling day, with Tuesday and Wednesday as alternates, and says samples are taken between sunrise and noon at about knee depth. The sample date is on every line of the tile. A reading from last Monday is last Monday’s water.
• Rain. The GLO says elevated bacteria levels “are commonly associated with rainfall and the related stormwater runoff.” It has no beach-by-beach rule, but its general advice is to curtail water contact for 48 to 72 hours after moderate to heavy rain. A Low from before a storm does not cover the days after it.

Every beach on the Lower Laguna Madre board

Every beach on the Coastal Bend board

Every beach on the upper coast board

Beaches nobody samples

The GLO says it samples 172 stations at about 61 beaches, and its FAQ names Aransas, Brazoria, Cameron, Galveston, Jefferson, Matagorda, Nueces and San Patricio counties. Its map layer also has stations in Harris County, at Sylvan Beach Park, and in Kleberg County, at Bird Island and Malaquite Beach. Those are on the tile too.

Willacy, Refugio, Calhoun, Jackson and Chambers counties have no Beach Watch beach at all, and the tile on those towns’ pages says so. Neither does Baffin Bay in Kleberg County. A beach nobody samples is not a clean beach. It is a beach with no result.

Getting alerts

The GLO offers email alerts for the beaches you choose. Sign up on texasbeachwatch.com and tick the beaches you want. For questions, the program’s number is 1-800-998-4GLO.

Why the GLO samples

The federal Beaches Environmental Assessment and Coastal Health (BEACH) Act, passed by Congress in 2000, requires coastal states, working with the EPA, to monitor coastal recreation waters next to public beaches and to notify the public when the standards are exceeded. In July 2001 the Governor’s office appointed the GLO as the lead state agency for the Act, because of the Beach Watch program it already ran. The program is funded by the EPA and administered by the GLO. In 2025 it collected 7,871 samples and issued 401 advisories.

Sources

• Texas General Land Office, Texas Beach Watch — the interactive map; the Low, Medium and High levels and the EPA’s 104 limit; the FAQ on the BEACH Act, how many stations and how often, what an advisory means and how long it lasts, where the bacteria come from, rain, and using a beach under an advisory; who posts signs; the 5 and 24,196 limits; what the program does not test for; and the health information taken from the EPA’s national beach guidance
• Texas General Land Office, Beach Watch map layer (BW2025_Summary) — the station rows the tile reads: beach, county, level, count and sample date
• Texas Beach Watch, sign up for email alerts — the alert sign-up and the list of sampled beaches by county
• Texas Beach Watch Quality Assurance Project Plan, 2025-2026 — local governments and signs, resampling in practice, sampling day, time and depth, and children as an at-risk population
• Texas Beach Watch flyer — what the green, yellow and red levels tell beachgoers
• Texas General Land Office, press release, May 20, 2026 — where Enterococcus comes from, that the GLO does not close beaches, and the 2025 sample and advisory totals
• Texas General Land Office, press release on Beach Watch alerts, June 13, 2023 — alerts for chosen beaches, and resampling every 24 to 48 hours