If you’re working in the heat, you need to stay hydrated.

Why? According to the CDC and OSHA, drinking enough water is one of the most important ways you can prevent heat illness. And it’s important for your long-term health, too. Research has connected repeated episodes of dehydration caused by working in the heat with chronic kidney disease, according to an interdisciplinary roundtable of 51 experts whose work was published in the science journal GeoHealth.

And when people are dehydrated, they’re not just putting themselves at risk. In hot environments, dehydration lowers alertness, increases fatigue and impairs cognitive function, which undermines overall health and safety in the workplace, according to the GeoHealth paper. 

And the danger of extreme heat is getting higher every year, with 18 of the last 19 summers being the hottest on record, as of 2022. That's part of the reason why OSHA introduced a National Enforcement Program on heat in 2022, which allows the agency to conduct proactive inspections and encourage businesses to provide training, rest, shade – and water.

But hydration doesn’t just magically happen on its own. Here are five tips for helping people stay hydrated on the work site.

Encourage People to Drink Water^*

* In sufficient quantities, at frequent intervals

When you’re working in the heat, you can’t just wait for your body to tell you to drink. If you feel thirsty, you’re already well on your way to dehydration. In one study, workers drank only about half as much fluid as they were losing through sweat outside of their lunch breaks, leading to some dehydration. It’s important to remind workers to drink water regularly.

How much water is enough? NIOSH recommends that people working in the heat drink one 8-ounce cup of water ever 15 to 20 minutes. That’s 24 to 32 ounces of water per hour – but don’t try to drink it all at once. It’s more effective to drink small amounts frequently than to drink larger amounts infrequently.

Put the Water in Reach

If it’s too much time and effort to get to a water station, you’re less likely to take the small, frequent drinks that are best at maintaining hydration.

OSHA recommends making water available in a location that’s near the work, familiar to workers and easy to access. And in California, having water close as possible is required by law. Under Cal/OSHA regulations, employers must keep water as close as can reasonably be accomplished to encourage frequent water consumption.

What can you do to make water easy to get to? It’s a best practice to put water in several locations when employees are spread out over a large area. For example, in a multistory construction site, you can put beverage dispensers on every floor where people are working. And if obstacles prevent easy access to water stations, consider alternatives like water jugs or personal water bottles. Water doesn’t need to be in a shade structure – you can place it closer to the work.

Remember Hydration at Home

It’s surprisingly common for people to be dehydrated when they show up for work, even if they know they’ll be working hard in the heat. Studies summarized in the GeoHealth paper found that 40% to 70% of workers are dehydrated when they arrive for their shifts.

And that’s definitely starting things off on the wrong foot. When you’re dehydrated at the start of the day, you’ll need to drink even more fluid than you’re losing through sweat just to rehydrate yourself. Drinking the recommended 8 ounces every 15 to 20 minutes might not be enough.

Encourage workers to drink enough water after work to replace any remaining water loss after work. According to NIOSH, most people need a few hours to replace what they’ve lost through sweat, and starting sooner puts less strain on your body. Alcohol can also cause dehydration.

Offer the Right Beverages

Water is great. Drinking water is almost always enough for you to stay hydrated, as long as you’re regularly eating meals to replace the salt you lose by sweating, according to NIOSH.

That said, for jobs lasting more than two hours, OSHA recommends that employers provide sports drinks or other electrolyte-containing beverages to replenish salts.

And there’s evidence that workers may drink more fluids when sports drinks are available because they prefer the taste, especially when the drinks are kept cold. That said, water should be the preferred beverage according to the GeoHealth paper, because of the long-term health implications of the extra sugar intake associated with many sports drinks.

NIOSH also recommends avoiding energy drinks. Some have much more caffeine than a cup of coffee, and it's often difficult to tell from the packaging how much caffeine they contain. High caffeine levels can affect your heart, especially when you’re working in the heat. And while some energy drink options are sugar free, other options have as much or more sugar than a soda, which can be unhealthy in excess. 

Clean the Bathroom

There are so many good reasons to maintain an adequate number of clean and sanitary toilet facilities on a work site. It helps prevent the spread of illness and other adverse health effects for one thing. And for another, it’s required by OSHA.

But OSHA’s requirements are really just a minimum. Going above and beyond has benefits. It can make people happier on the job – and it can make them more likely to drink enough water, too. According to the GeoHealth article, it’s common for people who have minimal access to bathrooms to voluntarily restrict their fluid intake, and access to a clean bathroom can influence a person’s desire to drink during their work shift.

Frequently Asked Questions 

Q: Is it possible to drink too much water when you’re working in the heat?

A: According to NIOSH, you shouldn’t drink more than 48 ounces (one and a half quarts) of fluid per hour while working, because this can cause the concentration of salt in the blood to become dangerously low.

Q: Do caffeine-containing drinks like coffee, tea and soda lead to dehydration?

A: Caffeine is a diuretic, which means it causes your body to make more urine. It would be natural to believe that caffeine-containing beverages could be dehydrating because of their diuretic properties. But most research suggests that the fluid contained in these drinks balances their diuretic effects, meaning that they don't promote dehydration. For example, one study found that a moderate amount of coffee (four cups per day) did not lead to dehydration. But keep in mind that high amounts of caffeine can affect the heart in ways that are risky when working in the heat, which is why NIOSH advises that workers avoid energy drinks.