CWS CWS Hardness, Scale & Corrosion Control

Question 1

What is the primary cause of scale deposits in water heaters and pipes in the US?

Accepted Answer

Calcium and magnesium carbonate precipitation

Answer

High dissolved oxygen

Answer

High total dissolved solids

Answer

Elevated chlorine levels

Question 2

The Langelier Saturation Index (LSI) is used to predict water's tendency to:

Accepted Answer

Form scale or corrode pipes

Answer

Filter sediment

Answer

Remove chlorine

Answer

Soften water

Question 3

At what LSI value is water considered balanced (neither scale-forming nor corrosive)?

Accepted Answer

LSI = 0

Answer

LSI = -1.0

Answer

LSI = +1.0

Answer

LSI = +2.0

Question 4

Which water condition is most likely to cause red staining on fixtures and laundry?

Accepted Answer

High iron content

Answer

High hardness

Answer

High manganese

Answer

High sulfates

Question 5

Galvanic corrosion in plumbing is most likely to occur when:

Accepted Answer

Two dissimilar metals are in direct contact in the presence of water

Answer

Water is too soft

Answer

Water temperature is below 50°F

Answer

Chlorine residual exceeds 1 ppm

Question 6

A customer reports blue-green staining on their copper fixtures. This most likely indicates:

Accepted Answer

Low pH corrosive water attacking copper pipes

Answer

High manganese

Answer

High hardness

Answer

Excessive chlorine