PHOENIX, Arizona Tap Water Quality

What this violation means

Total coliform bacteria are themselves usually harmless, but their presence signals that the water distribution system has a vulnerability — typically a cracked pipe, loss of pressure, or back-siphonage — that could allow disease-causing pathogens to enter. Repeated coliform-positive samples trigger mandatory utility investigation.

Recommended precautions

• →If your utility issues a boil-water advisory, boil all drinking and cooking water for at least one minute.
• →Use bottled water until the advisory is lifted.
• →Ice from icemakers and beverages made before the advisory should be discarded.
• →UV light and chlorination both kill coliform bacteria — most home filters do not.

What this violation means

Arsenic is a known human carcinogen that occurs naturally in groundwater across many parts of the United States, especially the Southwest and parts of New England. Long-term exposure even at low levels has been linked to bladder, lung, and skin cancer, as well as cardiovascular disease and developmental effects in children.

Recommended precautions

• →Reverse osmosis filtration removes arsenic effectively.
• →Distillation also removes arsenic — point-of-use distillers work for drinking and cooking water.
• →Boiling does NOT remove arsenic. It actually concentrates it as water evaporates.
• →If your well water has arsenic, test annually and treat at the point of entry.

What this violation means

Fluoride at the optimal level (~0.7 mg/L) reduces tooth decay, which is why most US utilities add it. The MCL of 4.0 mg/L exists to protect against skeletal fluorosis from naturally high-fluoride groundwater, while the EPA's secondary standard of 2.0 mg/L addresses dental fluorosis in children.

Recommended precautions

• →Reverse osmosis removes fluoride; standard carbon filters do NOT.
• →If your child uses fluoride toothpaste and drinks fluoridated water, supervise brushing to limit ingestion.
• →Bone meal supplements often contain fluoride and should be used cautiously.

What this violation means

Lead is a potent neurotoxin with no safe exposure level. In drinking water it primarily enters via corroded lead service lines, lead-soldered copper pipes, and brass fixtures. Children under 6 and pregnant women face the highest risk because lead disrupts developing nervous and skeletal systems.

Recommended precautions

• →Run cold tap water 30–120 seconds before drinking or cooking, especially after the tap has been unused for hours.
• →Never cook with hot tap water — heat increases lead leaching from pipes.
• →Use an NSF/ANSI 53 certified filter for lead removal (carbon block or reverse osmosis).
• →If you have children, get blood lead levels tested by your pediatrician.

What this violation means

Total coliform bacteria are themselves usually harmless, but their presence signals that the water distribution system has a vulnerability — typically a cracked pipe, loss of pressure, or back-siphonage — that could allow disease-causing pathogens to enter. Repeated coliform-positive samples trigger mandatory utility investigation.

Recommended precautions

• →If your utility issues a boil-water advisory, boil all drinking and cooking water for at least one minute.
• →Use bottled water until the advisory is lifted.
• →Ice from icemakers and beverages made before the advisory should be discarded.
• →UV light and chlorination both kill coliform bacteria — most home filters do not.

What this violation means

Haloacetic Acids (HAA5) are the second major group of disinfection byproducts after TTHMs. They form by the same mechanism — chlorine reacting with organic matter — and pose similar long-term cancer risks. Utilities are required to test quarterly at distribution-system locations to track HAA5 levels.

Recommended precautions

• →Activated carbon filtration removes most HAA5.
• →Reverse osmosis is highly effective.
• →Unlike TTHMs, HAA5 do not significantly off-gas. Use treatment rather than aeration.
• →Long-term ingestion is the primary concern, not short-term skin contact.

What this violation means

E. coli detection is an EPA Tier 1 acute violation, requiring same-day public notification. It confirms that fecal matter has entered the drinking water supply, posing immediate health risks — particularly to children, the elderly, and immunocompromised individuals.

Recommended precautions

• →Do not drink the water until the utility has lifted the advisory.
• →Boil water for at least one minute (three minutes at elevations above 6,500 ft).
• →Disinfect dishes and surfaces that touched contaminated water.
• →Seek medical attention if you develop bloody diarrhea or persistent vomiting.