Worksheet Grade 6 Science

Drayton's Aging Water Mains: Choosing What to Replace First

A grade 6 science worksheet where students weigh cost, age, and location to plan a fictional town's limited water-main replacement program.

Grade: Grade 6
Subject: Science
Material: Worksheet
Time: 35 min
Prep: No prep
Materials: None

Standards

6.RP.A.3 Common Core Math

Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations, including finding a percent of a quantity and converting measurement units.

How this material aligns: Items 1 and 5 ask students to express parts of the pipe system as percents, such as 12 of 50 miles, applying the percent reasoning this standard targets.

All materials for 6.RP.A.3 →

MS-ETS1-1 NGSS

Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

How this material aligns: Items 7 and 8 have students state the criteria and constraints Drayton must weigh before replacing pipes, matching this standard's call to define a design problem with precision.

All materials for MS-ETS1-1 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will calculate what fraction and percent of a pipe system is aging and how long a replacement plan will take.
Students will identify criteria and constraints a town must weigh when it can only replace a few pipes each year.

Vocabulary

Water main: A big underground pipe that carries drinking water beneath the streets to a neighborhood. Smaller service lines branch off it to reach each building.

Also: infrastructure, criteria, constraint

Teacher overview

Buried water pipes do not last forever, and towns rarely have the money to replace them all at once. Across the country, EPA estimates about $625 billion in drinking-water investment is needed over 20 years, and a water main breaks somewhere roughly every two minutes. This worksheet puts students in charge of pipe planning for Drayton, a fictional town, where they weigh age, cost, and location to decide what to fix first.

Drayton's Aging Water Mains: Choosing What to Replace First — Grade 6 Science

Name: ____________________________ Date: ______________

Student Worksheet

Use these facts about Drayton (a fictional town) for the problems below.

Drayton has 50 miles of water main in all.
12 miles of that pipe are more than 80 years old.
The town can replace 4 miles each year.
Replacing pipe costs Drayton about $600,000 for each mile.

What percent of Drayton's 50 miles of water main is more than 80 years old? (Find what percent 12 is of 50.)
At 4 miles replaced each year, how many years will it take to replace all 12 of the oldest miles?
At about $600,000 per mile, how much will it cost Drayton to replace all 12 of the oldest miles?
Drayton's yearly pipe budget is $2,400,000. At $600,000 per mile, how many miles can it replace in one year?
If Drayton replaces 4 of its 50 miles this year, what percent of its whole system is replaced this year?
A water main breaks somewhere in the country about every 2 minutes. About how many breaks is that in one hour?
Drayton can only replace 4 miles a year. Name two pieces of information the town should use to decide which pipes to replace first.
The oldest pipes break most often, but some of them run under a hospital and some run under empty fields. Explain why Drayton might not simply replace its pipes in order of age.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key

Answer: 24 percent.
12 divided by 50 = 0.24, which is 24 percent of the system.
Answer: 3 years.
12 old miles divided by 4 miles per year = 3 years.
Answer: $7,200,000.
12 miles times $600,000 per mile = $7,200,000.
Answer: 4 miles.
$2,400,000 divided by $600,000 per mile = 4 miles in one year.
Answer: 8 percent.
4 divided by 50 = 0.08, which is 8 percent of the whole system in one year.
Answer: 30 breaks.
60 minutes divided by 2 minutes per break = 30 breaks in an hour.
Answer: Accept any two useful pieces of information, such as which pipes are oldest, which break most often, how many homes each pipe serves, whether a pipe runs under a hospital or busy road, and how much each replacement costs. These are the criteria the town uses to rank the work.
Answer: Age is not the only thing that matters. A pipe under a hospital serves people who cannot lose water safely, so a break there causes more harm than a break under an empty field. The town must weigh how many people a pipe serves and how much damage a break would cause, not just how old the pipe is.

Differentiation

Support

Provide the division set-ups already written for items 1 through 5 (for example, "12 divided by 50" and "$2,400,000 divided by $600,000") so students focus on computing and interpreting rather than deciding which numbers to use. Allow a calculator throughout.

Extension

Ask students to build a simple three-row ranking table for three imagined Drayton pipes, each with an age, a break count, and the number of homes it serves, then decide which to replace first and write two sentences defending the order using the criteria from item 7.

ELL supports

Pre-teach water main, criteria, and constraint with plain definitions and a picture of a pipe under a street. Provide the sentence frame "Drayton should fix ___ first because ___" for items 7 and 8, and allow answers as short phrases.