Is Arizona Tap Water Safe To Drink? – Get The Facts!

The water supply in Arizona often has contaminants in it that makes it unsafe to drink. Because the quality of your water depends on where you live and where your water supply comes from, this post has everything you need to know about the tap water in Arizona.

The tap water in Arizona is safe to drink. Arsenic and nitrate are the contaminants of greatest concern for residents with private wells, but all contaminants found in city supplied tap water are below the safe legal limits set by the EPA.

Contaminants such as arsenic, nitrate, trihalomethanes, trichloroethylene and tetrachloroethylene have been found in different areas of Arizona. So, check out the information below to find out not only where contaminants have reached dangerous levels, but also what the water issues are in Arizona’s major cities and where the water supply comes from.

Is Arizona Tap Water Safe To Drink?

Arizona tap water is safe to drink!

As a matter of fact, the tap water in Arizona is actually safer to drink than many other states, such as Florida or Nevada.

The community and public water systems in Arizona disinfect the water supply, and more importantly treat the water to remove contaminants.

Basically, it’s their job to make sure contaminants stay below the legal concentration limits. These are legal limits set in line with the Safe Drinking Water Act – which is a federal law!

According to the Environmental Protection Agency (EPA) the tap water in Arizona is considered safe to drink because contaminants, like arsenic or nitrate, stay below the maximum concentration levels.

But, because some contaminants might have survived the treatment process, water systems monitor the water before it reaches our taps. To do this they take regular samples at the treatment plant and test them for up to 90 contaminants!

They even take samples of tap water from peoples homes too – All to make sure it meets the federal standards and is ‘safe’ for people to drink!

The contaminants of greatest concern in Arizona are:

  • Arsenic
  • Nitrate
  • Trihalomethanes (TTHMs)


Arsenic naturally occurs in rocks and is actually only toxic when it’s found in water at really high levels. According to the EPA, arsenic gets into our water supply because the natural erosion of rocks by wind and water removes the arsenic and allows it to dissolve in water.

In Arizona, arsenic is only found in drinking water that comes from groundwater.

In fact, the Office of Environmental Health at the Arizona Department of Health Services says…

“… arsenic is present in almost all groundwater supplies”.

Office of Environmental Health

Fortunately, most of the time it is only private wells that depend on groundwater for their water supply, but some water systems in cities (like Phoenix) can also use a small amount of groundwater. 

According to the University of Arizona, there is more than 100,000 domestic wells used in Arizona. This means that approximately 5% of Arizona residents get their drinking water from groundwater that is naturally high in arsenic.

This may not sound like a lot of people, but the Office of Environmental Health says that…

“… private wells are the primary source of water for rural residents of Arizona…”

Office of Environmental Health

So, if you do use a private well for your drinking water supply, the Office of Environmental Health recommends testing your water before using it for drinking or cooking – And if arsenic is in your water at high levels (more than 10 parts per billion) that a reverse osmosis system can remove it.

Amazon has a great range of kits that specifically test for arsenic in water. But be careful, the cheaper ones ($25-50) have a really poor detection limit and may not be able to tell you if arsenic is in your water above the legal limit (10 parts per billion). While the more expensive ones (>$215) often need you to send off your water to a lab – which costs even more money.

Luckily, there is a testing kit that not only tests for arsenic in water but at detection levels of <1, 2, 3, 4, 5, 6, 7, 8, 10, 13, 20, 25, 30, 40, >50, >80, >120, >160 parts per billion!! Amazon sells this testing kit here, which actually comes with 50 tests.


Nitrate in our water supply can be a real problem because it’s colorless, odorless and tasteless, which makes it is almost impossible to detect without proper testing.

Since 2012, a total of just 4,360 Arizona residents have been exposed to high concentrations of nitrate. The number of people affected is quite low because water systems remove nitrate during the water treatment process.

In fact, the last time residents were exposed to high concentrations of nitrate was in 2016.

According to the Arizona Department of Water Quality, some residents in Pinal County that are serviced by Johnsons Utility water system had nitrate in their drinking water higher than the safe legal limit. Fortunately, this was limited to just 2 days – Oct. 27 and Nov. 21, 2016.

Nitrate normally gets into our water supply when we source our water from groundwater. But high concentrations of nitrate in groundwater almost always comes from human sources, like septic systems, and agricultural or industrial areas.

So, unfortunately if you get your drinking water from a well it is possible your water could be high in nitrate – and you wouldn’t even know it!

The University of Arizona advises nitrate levels in drinking water can be lowered by 3 different treatment methods:

  • Distillation
  • Reverse osmosis
  • Ion exchange

They also note that carbon filters and standard water softeners do not remove nitrate.

Even more important, is their advice NOT to boil the water. Because boiling water means some water evaporates, it actually INCREASES the nitrate concentration.

Trihalomethanes (TTHMs)

Trihalomethanes are contaminants that form when chlorine, used by water treatment plants to disinfect our drinking water, combines with natural organic materials, like leaves and manure.

According to The Arizona Republic newspaper…

“Drinking water with high levels of TTHM over long periods of time can increase the rate of particular ailments such as cancer and liver, kidney and central nervous system problems”.

TTHMs are not typically a problem for drinking water that comes from groundwater. This is because groundwater does not have enough organic materials to form large amounts of TTHM – unfortunately, water in rivers and lakes do!

In recent years there have been a number of times that TTHMs have been higher than the safe legal limit in Arizona, including:

  • 2004 & 2005 Tempe
  • 2005 Glendale
  • 2005 Phoenix
  • 2005 & 2006 Scottsdale
  • 2016 Tempe
  • 2017 Gilbert
  • 2019 Chandler

So, while TTHMs can be found in Arizona’s drinking water, it certainly doesn’t happen very often or for a long period of time – and remember the negative health effects associated with TTHMs are because of long-term exposure. Odds are TTHMs will not be a problem in your water!

Major cities:

In general, Arizona tap water is safe to drink. But, it really does depend where you live and which water system treats your water supply. Here is some information about the water quality in Arizona’s 3 biggest cities:


On the whole, the tap water in Phoenix is actually really good, and safe to drink!

But, there are a couple of problems with Phoenix’s water supply that don’t always impact the drinking water – but has caused some problems in the past, and could again in the future.

For example, according to KTAR news…

“Arizona is one of three states in which tap water has the highest average statewide levels of chromium-6”.


In fact, Arizona has the highest level of all 50 states.

You might remember that chromium-6 is the carcinogen that featured in the 2000 “Erin Brockovich” movie.

However, the Phoenix Water Services Department says that information is really misleading.

It turns out that high levels of chromium-6 is only found in Phoenix’s groundwater – and only 2 percent of drinking water comes from groundwater, according to the assistant director of Phoenix Water Services Department.

More concerning is the toxic plume of contaminated water in central and west Phoenix. It was first noticed in 1987, and is so well known it actually has its own name! – the West Van Buren site.

According to The Arizona Republic, the toxic water came from dry cleaners and metal factories dumping harmful chemicals around their plants.

For decades toxic chemicals were dumped, trichloroethylene (TCE) and tetrachloroethylene (PCE) – known carcinogens, have even been found in this water.

Fortunately, this toxic mess is also limited to the groundwater, with the water only ever used at agricultural wells for some irrigation and never for drinking water.

So, because 98% of the drinking water in Phoenix is water from rivers and lakes, which is mixed in with the 2% groundwater – chromium-6, trichloroethylene and tetrachloroethylene are really never a problem in the water that comes out of our taps at home.

But if you live in the suburbs of the Phoenix area and use a well as your drinking supply instead of the city supply, you should probably have your water tested.


Do you live in Tucson? Well, lucky you!

Your water is not only safe, but also better than Chandler, Glendale, Mesa, Phoenix, Scottsdale or Tempe!

That’s because contaminant levels are rarely a problem in Tucson. Sure some arsenic, trihalomethanes and uranium have occasionally been found in the water over the last decade, but it has been at such low concentrations it is not considered a problem.

In fact, the concentrations are so low that not even the EPA, Arizona Department of Environmental Quality or the Environmental Working Group (EWG) considers them high enough to report, let alone worry about!

There is actually only 1 thing in Tuscon’s water that could cause a problem in the future.. and that’s the harmful and hard-to-eliminate toxins from firefighting foam.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are the chemicals found in firefighting foam that have made their way into the groundwater.

Currently, the concentrations have only reached high levels at places like Luke Air Force Base, in Maricopa County.

It was found in Tuscon’s water, back in 2014, but at concentrations too low to worry about – both then and now.


Mesa water is safe to drink! Actually, it has some amazingly clean drinking water!

In fact, in the last 8 years not once has a contaminant been found at high concentrations (higher than the legal limit).

About the only issue that Mesa occasionally has is an aesthetic one – the tap water can be cloudy sometimes.

According to The Arizona Republic, the tap water becomes cloudy

“… when the city temporarily switches from using surface water to well water.”

So, even when the water in Mesa is cloudy, it is still safe to drink!

Where does Arizona tap water come from?

Around 57% of Arizona’s tap water comes from surface water (water that’s found in rivers and lakes), with the majority sourced from the Colardo River.

So, where does the rest of the water come from? Well, Arizona’s tap water is sourced from

  • 57% Surface water
  • 40% Groundwater
  • 3% Reclaimed water

Surface water

I found it really interesting to learn that Arizona’s water is sourced from different rivers inside the state.

Actually, 40% is from the Colorado River alone! – This is a combination of on-river water and water from the Central Arizona Project. Another 10% comes from the Salt and Verde Rivers – with the remaining 3% coming from a bunch of smaller rivers throughout the state.


So, it turns out that the 40% of Arizona’s tap water that is sourced from groundwater, actually comes from lots of different aquifers.

Aquifers are spaces where water is naturally stored deep underground, in between layers of rock and sediment, like limestone or clay.

The groundwater is restocked whenever it rains, because the rainwater enters the soil and slowly filters down through the layers and into the aquifer.

Arizona’s drinking water comes from 2 main aquifers systems:

  1. The Colorado Plateau Aquifers
  2. The Basin and Range Aquifers 

These include southern aquifers like:

  • Santa Cruz Aquifer
  • San Pedro Aquifer

And these northern aquifers:

  • Coconino-De Chelly Aquifer
  • Dakota-Glen Aquifer
  • Mesaverde Aquifer

And a whole lot more in the east, where the basin and range aquifer system is. It is a massive system, made up of a huge number of smaller basins and aquifers – it actually stretches across Nevada, and parts of California, Idaho, Oregon, and Utah!

Reclaimed water

Reclaimed water is tap water, but it’s not drinking water!!

That’s because ‘reclaimed water’ is actually wastewater!

The wastewater, or sewage, is treated at a Wastewater Treatment Plant. The water is then thought to be clean and safe enough to be used as tap water. But only for things like watering the garden, it is not okay to drink!

The Water Division of the Arizona Department of Environment Quality says that the reclaimed water helps to…

“… conserve potable water for human consumption and domestic purposes”.

Arizona Department of Environment Quality

So, basically while we don’t actually drink the reclaimed water, if we use it for other things it means we use less of our precious drinking water.

It certainly seems a waste to use our drinking water for our gardens or for large scale irrigation. Especially since Arizona is a really dry place, it makes perfect sense to me to conserve our drinking water.

Is Arizona tap water fluoridated?

Only 58% of tap water in Arizona has fluoride added to it, according to the United Health Foundation.

Fluoride isn’t just added to our water by community and public water systems, it also occurs naturally in our water!

Fluoride comes from the erosion of minerals and rocks and goes into our groundwater and surface water, and from there, into our water supply. If you would like to learn more about why fluoride is in our water and about the history of fluoridation you can read about it here, in a post I wrote.

The Arizona Department of Health Services says the water in Arizona has…

“… naturally occurring fluoride at 0.2 to 0.5 milligrams per liter of water (mg/L)”.

Arizona Department of Health Services

The EPA recommendation is only 0.7mg/L for tap water – so a lot of Arizona’s water has close to the recommended amount before any is even added!

Besides that, the State of Arizona doesn’t even mandate fluoridation – it’s just up to each local government to decide if they want fluoride added to their water or not.

So, while The City of Phoenix does add fluoride to the water, The City of Tucson doesn’t!

If you want to check if the water system that services your area adds fluoride to your water- then you can check at the CDC’s website “My water’s fluoride”. The website lets you search your county and local water system. You can get to their main page here.

How hard is Arizona Water?

Most of Arizona has ‘very hard’ water, but some areas do have water that is slightly softer – mostly in the north, north-east, where the water is classified as ‘hard’.

Water is called ‘hard’ when it is high in minerals like calcium and magnesium The USGS says waters are actually classified based on the amount of calcium carbonate in water:

  • Soft = 0 to 60 mg/L of calcium carbonate
  • Moderately hard = 61 to 120 mg/L
  • Hard = 121 to 180 mg/L
  • Very hard = more than 180 mg/L

So, that means most of the tap water in Arizona has more than 180mg/L of calcium carbonate in it.

Phoenix actually has an average of 291mg/L – which is some very hard water!!

While the water in Flagstaff ranges from soft to seriously very hard, which is a big variation!

The water in Flagstaff is so different because it depends on where you live and which water system provides your water. Flagstaff City Council says the…

“… water hardness varies from 25 mg/L to 325 mg/L depending on the source of production”.

The City of flagstaff


“The average throughout the (Flagstaff) system is 125 to 200 mg/L”.


Related Questions

How much water should you drink in a day in Arizona? Experts recommend people in Arizona should drink at least 2 L of water each day. That amount increases to 1 to 2 L per hour for people who are outdoors during hot weather, says the Arizona Department of Health Services information.

Do I need a water softener in Arizona? The very hard water in Arizona can cause scaling in plumbing and any connected appliances, which is a build-up of calcium or magnesium. Scaling does not make the water unsafe to drink, but can reduce the lifespan of pipes and appliances. A water softener can be used to remove the mineral build-up. Salt-based and salt-free water softeners are effective and can be used in Arizona.

Recent Posts