Vegas Valley Water Guide

Boulder City's water and the softener it needs

Boulder City buys treated Lake Mead water from the Southern Nevada Water Authority and delivers it through its own city system. The city gives one approximate hardness figure for all of it.

How hard is Boulder City water?

Figures published by City of Boulder City (Water and Sewer). The dial setting is the number to enter on your softener.

City or areaHow hardRange (grains per gallon)Softener dial settingSource
Boulder CityExtremely hardabout 1717City of Boulder City (Water and Sewer), annual water quality report, 2026 (2025 data)

1. How many people live in your home?

the number your kit shows, in grains per gallon
Your water is
Extremely hardAbout 200 lb of minerals flow into your home each year
Softener size to buy
32,000-grain
the size number on the box
Salt it will use
About 11
40 lb bags a year
Set the hardness dial to
17
recharges about every 8 days

What the dial setting means

This is the number to key into your softener's control head (the box on top of the tank) where it asks for water hardness, often shown as "Hardness" or "gpg". It is how the softener knows how much hardness it is taking out of each gallon.

When the resin inside is full of minerals, the softener recharges: it washes the resin with brine from the salt tank and sends the minerals down the drain. For your household that works out to about every 8 days, and it happens automatically.

Too low a number lets hard water through between recharges. Too high a number makes it recharge sooner than it needs to, using extra salt and water.

Boulder City gives one approximate average for the whole city. Source: City of Boulder City (Water and Sewer), annual water quality report, 2026 (2025 data).

Nobody pays to be listed or ranked here, and we don't make, sell, rent or install softeners or filters.

How this figure was measured

Who published it

Water authority
City of Boulder City (Water and Sewer)
About the authority
The Boulder City public water system, which buys treated Lake Mead water from the Southern Nevada Water Authority. A public agency; no company supplied or paid for this figure.
Type of source
Annual water quality report. Every community water system in the U.S. must publish one each year under the federal Safe Drinking Water Act, so it is the utility’s own official record of what is in its water.
Data year
2026 (2025 data)
Last checked
16 October 2026, against the original document

What the figure is

What was measured
Average hardness, in grains per gallon and parts per million: 290 mg/L, published as 17 grains per gallon
Area covered
The whole Boulder City water system
How it was sampled
One approximate average for the city's water, given in the report.
Where the water comes from
Treated Colorado River water drawn from Lake Mead and treated at the Alfred Merritt Smith Water Treatment Facility. The city gives Lake Mead's inflows as about 97 percent Colorado River.

How we use it

Figure we use
The document’s own grains-per-gallon figure (17).
Unit conversion
1 grain per gallon = 17.1 milligrams per litre (mg/L), the same as parts per million (ppm)
How we calculate
Daily hardness to remove = people × 75 gallons × grains per gallon. We pick the smallest standard size that lasts about 7 days between recharges, at 3,300 grains removed per pound of salt.
Limits
The city calls this figure approximate, and it may be carried over from earlier editions of its report. A home test result overrides it.

Lake Mead water, city delivery

Boulder City doesn’t treat its own water. It buys treated water from the Southern Nevada Water Authority, drawn from Lake Mead and cleaned at the Alfred Merritt Smith Water Treatment Facility, then distributes it through the city’s system. The city’s report gives Lake Mead’s inflows as about 97 percent Colorado River, with small amounts from the Virgin and Muddy rivers and the Las Vegas Wash.

About the figure

The city describes 17 grains per gallon as approximate and gives no range. It’s a sensible setting for most homes, but a test kit will tell you exactly where yours is, and the calculator above takes your result.

Sizing in Boulder City

Household Softener size Salt a year
One person 24,000 grains about 4 bags
Two people 24,000 grains about 7 bags
Three people 32,000 grains about 11 bags
Four people 40,000 grains about 14 bags
Five people 48,000 grains about 18 bags

Close to Henderson

Henderson, next door, gives a typical 18 grains per gallon from the same Lake Mead water. Softeners sized for either city will suit the other.

Questions about Boulder City water

How hard is Boulder City water?
The city's newest water quality report gives an average hardness of approximately 17 grains per gallon, or 290 parts per million.
Where does Boulder City's water come from?
Lake Mead. The water is drawn through the Southern Nevada Water Authority's intake, treated at the Alfred Merritt Smith Water Treatment Facility and delivered by the city.
Is Boulder City water harder than Las Vegas water?
Slightly, by the published figures: about 17 grains per gallon against the Las Vegas Valley Water District's 16, though both come from Lake Mead.