Worksheet Grade 6 Science

Marren Falls Water Works: Tracking Water Lost to Leaks

A grade 6 worksheet on non-revenue water where students find how many gallons a fictional utility loses to leaks and what percent of pumped water is lost.

Grade: Grade 6
Subject: Science
Material: Worksheet
Time: 35 min
Prep: No prep
Materials: Calculator (optional)

Standards

MS-ESS3-3 NGSS

Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.

How this material aligns: Items 9 and 10 have students explain and propose a monitoring method that locates hidden leaks, the design-to-minimize-a-human-impact reasoning this standard asks for.

All materials for MS-ESS3-3 →

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 through 8 use rate and percent reasoning to find gallons lost, the percent of pumped water lost, and a simplest-form ratio of billed water to pumped water.

All materials for 6.RP.A.3 →

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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 the gallons and percent of treated water a utility loses to leaks.
Students will find how much a utility must cut losses to reach a stated conservation goal.
Students will explain how metering pumped and billed water helps locate hidden leaks.

Vocabulary

Non-revenue water: Water that a utility treats and pumps but never gets paid for. Most of it escapes through leaks in old pipes, and some is lost to broken meters or theft.
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.
Distribution system: A distribution system is the network of pipes, pumps, valves, and storage tanks that carries treated water from a treatment plant to homes, schools, and businesses. Most of it is buried underground beneath streets.

Also: leak

Teacher overview

Water that a utility cleans and pumps into its pipes does not all reach paying customers. Some of it leaks out of old, cracked pipes underground before anyone can use it. Utilities call this "non-revenue water." Non-revenue water also includes meter errors and unbilled uses such as firefighting, but this worksheet treats all of it as leakage to keep the numbers simple. Finding it starts with a simple comparison: how much water was pumped into the system, and how much was billed at customers' meters. Across the country a water main breaks roughly every two minutes, so leaks are a constant problem for older systems. This worksheet uses the fictional Marren Falls Water Works to turn that comparison into ratio and percent practice. A common error to watch for: students subtract in the wrong order, so remind them that pumped water is always the larger number.

Marren Falls Water Works: Tracking Water Lost to Leaks — Grade 6 Science

Name: ____________________________ Date: ______________

Student Worksheet

The fictional Marren Falls Water Works pumps clean water into its pipes and reads customers' meters to bill them. Use these facts for every question.

Marren Falls pumps 800,000 gallons of water into the system each day.
Customer meters add up to 600,000 gallons billed each day.
For this worksheet, treat the gallons that were pumped but never billed as lost to leaks.

How many gallons per day does Marren Falls lose to leaks?
What percent of the water pumped into the system is lost? Show your work.
Over 7 days, how many total gallons are lost?
The utility sets a goal to lose no more than 10 percent of the water it pumps. At 800,000 gallons pumped per day, how many gallons is that?
How many fewer gallons per day must the utility lose to reach that goal?
Write the ratio of water billed to water pumped each day, in simplest form.
A repair crew finds and fixes one broken main that was losing 40,000 gallons per day. After the repair, how many gallons per day are lost?
After that repair, what percent of the pumped water is lost now?
Explain how metering both the water pumped into the system and the water billed at meters helps the utility find leaks it cannot see underground.
Name one method Marren Falls could use to find where its losses are highest, and explain how that method would reduce wasted water.

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: 200,000 gallons.
Pumped minus billed is 800,000 minus 600,000, which equals 200,000 gallons lost each day.
Answer: 25%.
200,000 lost divided by 800,000 pumped equals 0.25, which is 25 percent.
Answer: 1,400,000 gallons.
200,000 gallons per day times 7 days equals 1,400,000 gallons lost.
Answer: 80,000 gallons.
10 percent of 800,000 is 0.10 times 800,000, which equals 80,000 gallons.
Answer: 120,000 gallons.
The utility now loses 200,000 and wants to lose only 80,000, so 200,000 minus 80,000 equals 120,000 fewer gallons per day.
Answer: 3 to 4.
Billed is 600,000 and pumped is 800,000. Both divide by 200,000 to give 3 to 4.
Answer: 160,000 gallons.
The daily loss of 200,000 drops by 40,000, so 200,000 minus 40,000 equals 160,000 gallons.
Answer: 20%.
160,000 lost divided by 800,000 pumped equals 0.20, which is 20 percent.
Answer: If the utility knows it pumped 800,000 gallons but billed only 600,000, the missing 200,000 gallons must be leaking out somewhere. Comparing the two totals shows there is a hidden loss even when no leak is visible at the surface.
Answer: Answers will vary. Accept clear methods such as listening for leaks with sound sensors on pipes, checking flow in one zone at night when little water should be used, or replacing the oldest mains first. The explanation should connect the method to catching leaks so less clean water is wasted.

Differentiation

Support

Provide a filled-in first row that models item 1 (pumped minus billed) so students can see the subtraction set up before they try it. Let students use a calculator and a place-value chart to keep the large numbers lined up.

Extension

Ask students to figure out how many gallons per year Marren Falls loses at the original rate, then estimate how many typical households that lost water could have served if a household uses about 300 gallons per day. Have them state that comparison clearly.

ELL supports

Pre-teach "leak," "pumped," "billed," and "non-revenue water" with a simple diagram showing water leaving the plant, some dripping out of a cracked pipe, and the rest reaching a house. Allow short-phrase answers for items 9 and 10.

Extensions

Invite students to write a short letter to a fictional town council explaining why Marren Falls should spend money to replace old pipes, using the gallons-lost numbers from this worksheet as their evidence.