Your city's tap water, at a glance

Utility: NYC Department of Environmental Protection

Source water: Catskill/Delaware and Croton reservoir systems in upstate New York; the Catskill/Delaware supply is UV-disinfected under a filtration-avoidance program

One of the largest unfiltered surface supplies in the U.S. Older buildings may still have lead service lines or lead solder — run the cold tap before drinking if water has sat for hours.

Utility: Los Angeles Department of Water and Power (LADWP)

Source water: A changing blend of the Los Angeles Aqueduct (Eastern Sierra snowmelt), imported Colorado River and State Water Project supplies, and local groundwater

Hardness and taste shift with the supply blend through the year. Spot scaling on fixtures is common.

Utility: Chicago Department of Water Management

Source water: Lake Michigan, treated at the Jardine and Sawyer purification plants

Chicago has one of the largest counts of lead service lines in the U.S. (about 400,000 by the city's own estimate), so lead testing is especially worthwhile in older homes.

Utility: Houston Public Works

Source water: Surface water from Lake Houston, Lake Conroe and the Trinity River (Lake Livingston), plus some groundwater

A large surface-water system serving a fast-growing metro; boil-water notices after storms and main breaks are worth monitoring.

Utility: City of Phoenix Water Services

Source water: Salt and Verde rivers, Colorado River water via the Central Arizona Project, and a small share of groundwater

Among the hardest municipal water in the country — scale on fixtures, water heaters and kettles is the number-one complaint.

Utility: Philadelphia Water Department

Source water: Delaware and Schuylkill rivers

River supplies vary seasonally. Older rowhomes are a known lead-service-line risk.

Utility: San Antonio Water System (SAWS)

Source water: Edwards Aquifer plus Carrizo-Wilcox groundwater and other diversified supplies

Very hard aquifer water. Many households use softeners; taste is generally clean.

Utility: City of San Diego Public Utilities Department

Source water: Imported Colorado River and State Water Project water, local reservoirs and desalinated seawater in the regional mix

Very hard imported water. Expect white scale and spotty glassware.

Utility: Dallas Water Utilities

Source water: Lakes Ray Hubbard, Lewisville, Grapevine, Ray Roberts, Tawakoni and Lake Fork

Lake-sourced supply; seasonal earthy taste can occur in late summer algae season.

Utility: Austin Water

Source water: Colorado River via Lake Travis and Lake Austin

Lime softening at the plant keeps hardness moderate for central Texas.

Utility: JEA

Source water: Upper Floridan aquifer wells

Groundwater can carry a sulfur odor at some taps; hardness is moderate to high.

Utility: City of Columbus Division of Water

Source water: Scioto River, Big Walnut Creek and wellfields, softened at the plants

Spring agricultural runoff can raise nitrate in river sources; the utility monitors and blends.

Utility: Charlotte Water

Source water: Catawba River (Mountain Island Lake and Lake Norman)

Soft Piedmont surface water.

Utility: Citizens Energy Group

Source water: White River, Fall Creek, Eagle Creek and groundwater wells

Very hard water typical of central Indiana's limestone geology.

Utility: San Francisco Public Utilities Commission (SFPUC)

Source water: Hetch Hetchy Reservoir (Tuolumne River) plus local Bay Area reservoirs

Exceptionally soft Sierra snowmelt.

Utility: Seattle Public Utilities

Source water: Cedar River and South Fork Tolt River watersheds

Very soft mountain water from protected watersheds.

Utility: Denver Water

Source water: Mountain snowmelt from the South Platte and Blue River systems

Soft to moderately hard; Denver Water runs a long-term lead reduction program.

Utility: DC Water (treated by the Washington Aqueduct)

Source water: Potomac River

DC's 2001–2004 lead crisis drove one of the country's most watched lead service line programs.

Utility: Massachusetts Water Resources Authority (MWRA)

Source water: Quabbin and Wachusett reservoirs in central Massachusetts

Very soft reservoir water. Older homes may have lead service lines.

Utility: Metro Water Services

Source water: Cumberland River

Moderately hard river water.

Utility: Great Lakes Water Authority / DWSD

Source water: Detroit River and Lake Huron

Michigan's state lead rules are stricter than the federal baseline.

Utility: Portland Water Bureau

Source water: Bull Run watershed, with the Columbia South Shore Wellfield as backup

Among the softest city water in the U.S.; a new filtration facility is under construction.

Utility: Las Vegas Valley Water District (Southern Nevada Water Authority)

Source water: Lake Mead (Colorado River)

Very hard Colorado River water — softeners and RO units are common.

Utility: Memphis Light, Gas and Water (MLGW)

Source water: Memphis Sand Aquifer (deep artesian wells)

Often praised for its naturally filtered aquifer water.

Utility: Louisville Water Company

Source water: Ohio River, including riverbank filtration

Hard river water.

Utility: Baltimore City Department of Public Works

Source water: Loch Raven, Liberty and Prettyboy reservoirs, with the Susquehanna River as backup

Moderately hard reservoir water.

Utility: Milwaukee Water Works

Source water: Lake Michigan, treated with ozone

Milwaukee added ozone after the 1993 Cryptosporidium outbreak — one of the most studied waterborne events in U.S. history.

Utility: Albuquerque Bernalillo County Water Utility Authority

Source water: Rio Grande (San Juan–Chama Project water) and aquifer wells

Hard desert water; blend shifts between surface water and groundwater.

Utility: Tucson Water

Source water: Colorado River water via the Central Arizona Project (recharged and recovered) plus groundwater

Hard water; aquifer recharge keeps the system resilient in drought.

Utility: City of Sacramento Department of Utilities

Source water: American and Sacramento rivers plus groundwater

Soft river water; groundwater areas are harder.

Utility: Atlanta Department of Watershed Management

Source water: Chattahoochee River

Soft Piedmont river water.

Utility: Miami-Dade Water and Sewer Department

Source water: Biscayne Aquifer (lime-softened) and Floridan Aquifer

Softened at the plant; saltwater intrusion into the aquifer is a long-term concern.

Utility: City of Tampa Water Department

Source water: Hillsborough River, with aquifer and regional supplies

Hard water; taste can change in dry season.

Utility: Orlando Utilities Commission (OUC)

Source water: Lower Floridan aquifer, treated with ozone

Ozone treatment removes the sulfur taste common in Florida groundwater.

Utility: City of Minneapolis Water Treatment and Distribution

Source water: Mississippi River, lime-softened

Softened river water; seasonal taste changes in spring.

Utility: KC Water

Source water: Missouri River

Hard river water; the region surrounding the city has some of the hardest supplies in the Midwest.

Utility: City of St. Louis Water Division

Source water: Missouri and Mississippi rivers

River water treated at the Chain of Rocks and Howard Bend plants.

Utility: Sewerage and Water Board of New Orleans

Source water: Mississippi River

Boil-water advisories follow pressure drops — keep an eye on alerts.

Utility: Salt Lake City Department of Public Utilities

Source water: Wasatch canyon streams (City Creek, Parley's, Big Cottonwood) plus wells

Hard mountain-and-well water; blends vary by neighbourhood.

Utility: Pittsburgh Water

Source water: Allegheny River

Pittsburgh runs an active lead service line replacement program.

Utility: Cleveland Water

Source water: Lake Erie

Late-summer algal blooms in Lake Erie are monitored closely.

Utility: OKC Utilities

Source water: Lakes Hefner, Overholser and Draper, fed by Atoka and McGee Creek reservoirs

Hard lake water; taste and odor events can occur in summer.

Utility: Raleigh Water

Source water: Falls Lake and Lake Benson

Soft Piedmont lake water.

Utility: Honolulu Board of Water Supply

Source water: Basal groundwater aquifers on Oʻahu

Naturally filtered groundwater; aquifer protection is a top local issue.

Utility: Anchorage Water and Wastewater Utility

Source water: Eklutna Lake and Ship Creek

Very soft glacial-fed water.

Utility: Fort Worth Water

Source water: Eagle Mountain, Benbrook, Richland-Chambers and Cedar Creek lakes

Lake water; seasonal earthy taste can occur.

Utility: Veolia Water Idaho

Source water: Boise River plus groundwater wells

Hardness varies by well zone.

Utility: Toronto Water

Source water: Lake Ontario

Moderately hard lake water. Health Canada's lead guideline (5 µg/L) is stricter than the U.S. action level; Toronto offers free lead test kits.

Utility: Service de l'eau, Ville de Montréal

Source water: St. Lawrence River and Rivière des Prairies

Montréal is replacing its lead service lines city-wide; residents in pre-1970 homes should check their entrance pipe.

Utility: Metro Vancouver

Source water: Capilano, Seymour and Coquitlam reservoirs

Very soft rainforest water — naturally corrosive, so the region adds corrosion control.

Utility: City of Calgary

Source water: Bow and Elbow rivers

Hard water; scale is common in kettles and water heaters.

Utility: City of Ottawa

Source water: Ottawa River

Soft river water.

Utility: EPCOR

Source water: North Saskatchewan River

Hard prairie river water; spring runoff changes taste.

Utility: City of Winnipeg

Source water: Shoal Lake via a gravity aqueduct

Treated at the Deacon plant; moderately hard.

Utility: Ville de Québec

Source water: Saint-Charles River and the St. Lawrence River

Soft surface water.

Utility: Halifax Water

Source water: Pockwock Lake and Lake Major

Very soft lake water.

Utility: Thames Water (and others)

Source water: River Thames, River Lee and chalk aquifers

Some of the hardest water in Britain — limescale is a way of life.

Utility: United Utilities

Source water: Lake District reservoirs (Haweswater and Thirlmere)

Very soft upland water.

Utility: Eau de Paris

Source water: Groundwater springs plus the Seine and Marne rivers

Hard water from chalk and limestone sources.

Utility: Sydney Water (bulk water from WaterNSW)

Source water: Warragamba Dam and other protected catchments

Soft surface water.

Utility: Melbourne Water and retailers

Source water: Protected forested catchments such as the Thomson and Upper Yarra reservoirs

Very soft water from closed catchments.