Exploring Clark County Drinking Water
Clark County WA Drinking Water Utility, Water Sources:
Let’s look into Clark County’s drinking water supply!
Read the utility page here: https://www.clarkpublicutilities.com/residential‐customers/water‐service/
1. What is the average annual gallons of water used per residential customer of the Clark Public Water
Utility?
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2. Does Clark County add fluoride to the drinking water? Yes / No
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3. Does Clark County use chlorine to keep the drinking water clean? Yes / No
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Browse the American Dental Association’s information about fluoride here
https://www.ada.org/en/public‐programs/advocating‐for‐the‐public/fluoride‐and‐
fluoridation/fluoridation‐faq.
4. Would the American Dental Association recommend that children in Clark County should be (choose
one) :
(a) using fluoride toothpaste and/or taking dietary fluoride supplements (usually drops or small
dissolving pills)
(b) not using any fluoride
Explain why you chose (a) or (b):
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5. Do you personally agree or disagree with the American Dental Association’s guidance for keeping
children’s teeth healthy for life? Why? [There is NO ‘right’ answer. Just explain your opinion.]
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The City of Vancouver water is separate from Clark County water utility. City of Vancouver information is
here: https://www.cityofvancouver.us/publicworks/page/drinking‐water
Look at this site about fluoride in City of Vancouver water.
https://www.cityofvancouver.us/publicworks/page/information‐about‐fluoridation
6. Would the American Dental Association recommend that children on City of Vancouver water
should take dietary fluoride supplements (or use fluoride toothpaste), or not? Why or why not?
Type your answer here
View the link at the above Clark County utility that page provides to a geologic cross‐section of Clark
County’s aquifers, or go directly to the pdf:
https://www.clarkpublicutilities.com/wp‐content/uploads/2016/04/crossSectionAquifer.pdf
This is a cut‐away view through the earth, like if you could put a giant knife on the Earth between
Portland and La Center, and cut down through the top several rock layers, then look at the side of the
cut like you are looking at the layers of a cake.
To understand where the “knife” has “cut through”, open any mapping website or app and map a
driving route from “Portland” to “Tri‐Mountain Golf Course” (two of the labels near the ends of the
geologic cross‐section).
7.
This geologic cross‐section runs roughly:
(a) East – West
(b) Northeast – Southwest
(c) Northwest – Southeast
(d) North – South
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The "Well Completion Intervals" (thick black vertical lines) shown on this cross‐section show the depth
range from which each well draws its water when it is pumped.
8.
The name of the aquifer from which most of the water appears to be drawn is the:
(a) Upper Troutdale Aquifer
(b) Lower Troutdale Aquifer
(c) Recent Alluvial Aquifer
(d) Sand and Gravel Aquifer
(e) Fractured basalt formations
Type your selection here
Again at the Clark County public utility web page (https://www.clarkpublicutilities.com/residential‐
customers/water‐service/), click on the orange button below “Our Commitment to Quality” that says
“Read More.” Using the information in the document that it shows you, answer the following questions:
9. How much does FOUR gallons of drinking water from the tap typically cost a Clark Utility water
customer? (Answer in decimal dollars and cents, like 5 dollars and 43 cents would be 5.43)
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10. Using the information provided in the document, about how much might FOUR gallons of bottled
water cost the same person?
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11. What is one action – which you actually feel you could do and would be willing to do – that you
could take to help conserve water from your indoor water use?
Type your answer here