Worksheet Grade 8 Science

Rowancross Lane Lead Profile: Reading a Sequential Sample

A grade 8 science worksheet in which students read five sequential tap samples from a fictional home to locate the lead source and compare results to the action level.

Grade: Grade 8
Subject: Science
Material: Worksheet
Time: 35 min
Prep: No prep
Materials: Printed worksheet

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 7 through 10 use the sampling profile to decide which pipe section to replace, which is the monitoring and impact-reduction method this standard requires.

All materials for MS-ESS3-3 →

RST.6-8.7 Common Core ELA

Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).

How this material aligns: Students integrate the written description of the home's plumbing with the numerical sample table in items 1 through 6 to interpret the profile.

All materials for RST.6-8.7 →

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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 interpret a sequential sampling profile to locate the source of lead in a home's plumbing.
Students will compare measured lead concentrations to the federal action level and calculate a mean.
Students will explain why flushing a tap before sampling can hide a lead problem.

Vocabulary

Service line: A service line is the small pipe that connects the water main under the street to the plumbing inside one home or building. It is the last leg of the trip water makes to your tap.
Action level: A trigger number in lead and copper testing. If too many homes test above this level, the utility must take steps like improving treatment and telling the public.

Also: sequential sampling, stagnation, parts per billion, corrosion

Teacher overview

Lead almost never comes from a lake, a well, or a treatment plant. It comes from the pipe, solder, or brass fitting the water touches on its way to a tap, and the longer the water sits still in that pipe, the more lead dissolves into it. Utilities find the source by drawing several bottles one after another and reading them as a profile, because each bottle held water that was sitting in a different part of the plumbing. Students often assume a single tap sample describes a whole house; this worksheet uses a five-bottle profile from a fictional home to show why the order of the bottles matters as much as the numbers.

Rowancross Lane Lead Profile: Reading a Sequential Sample — Grade 8 Science

Name: ____________________________ Date: ______________

Student Worksheet

A technician visited a fictional home at 214 Rowancross Lane in the town of Thrushwood. Nobody had used water for six hours. Without letting the tap run first, the technician filled five one-liter bottles back to back from the kitchen faucet. Water travels from the street main, through the buried service line, into the interior pipe, and out the faucet, so the first bottle holds the water closest to the tap and the last bottle holds water that started in the street.

Bottle	Where that liter had been sitting	Lead (ppb)
1	Faucet and the brass fitting behind it	12
2	Interior copper pipe	4
3	First part of the buried service line	22
4	Middle of the buried service line	27
5	Water main under the street	3

Which bottle had the highest lead result, and how many parts per billion was it?
Bottle 5 held water from the street main. What was its result, and what does that suggest about the water in the main itself?
How much higher was bottle 4's result than bottle 2's?
The federal lead action level is 15 parts per billion. List the bottles that came in above 15.
That action level drops to 10 parts per billion in 2027. List the bottles that came in above 10.
Find the mean of the five bottle results.
Suppose the technician had run the tap for five minutes and then filled one bottle. That bottle would have looked much like bottle 5. Explain why that single flushed sample would hide the problem at this home.
Based on the profile, which part of the plumbing should Thrushwood replace first? Give the evidence from the table that supports your choice.
Thrushwood replaces the half of the service line under the street and leaves the half under the yard in place. Explain why the homeowner might still get high results after that work.
Using the profile, explain in two or three sentences where the lead in this home's water comes from and how it gets into the 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: 27 ppb.
Bottle 4, drawn from the middle of the buried service line, was the highest of the five results.
Answer: 3 ppb.
Bottle 5 held water from the street main, and its low result shows the main is not the source of the lead. The lead is picked up after the water leaves the main.
Answer: 23 ppb.
27 minus 4 equals 23 parts per billion higher in bottle 4 than in bottle 2.
Answer: Bottles 3 and 4.
Bottle 3 at 22 and bottle 4 at 27 are both above 15 parts per billion. Bottle 1 at 12, bottle 2 at 4, and bottle 5 at 3 are below it.
Answer: Bottles 1, 3, and 4.
Bottle 1 at 12, bottle 3 at 22, and bottle 4 at 27 all exceed 10 parts per billion, so the lower level in 2027 adds bottle 1 to the list.
Answer: 13.6 ppb.
12 plus 4 plus 22 plus 27 plus 3 equals 68, and 68 divided by 5 equals 13.6 parts per billion.
Answer: Flushing replaces the standing water with water straight from the main.
After five minutes of running, the bottle would hold water that had been in the street main rather than water that sat in the service line, so the result would look like bottle 5's low value and the high readings in bottles 3 and 4 would never appear.
Answer: The buried service line.
Bottles 3 and 4, which held water sitting in the service line, are far higher than the bottles from the interior pipe and the street main, so the service line is the source and should be replaced first.
Answer: Half the lead pipe is still in the ground.
Water still sits in the remaining lead pipe under the yard and keeps dissolving lead. Cutting and joining pipe also shakes loose particles of lead scale, so results can stay high or even rise for a while after a partial replacement.
Answer: The lead dissolves out of the service line and the brass fitting while the water sits still.
The reservoir and the treatment plant do not add lead. Water picks it up when it touches lead pipe and brass, and the six hours of stagnation gave lead time to corrode off those surfaces and dissolve into the water that filled bottles 1, 3, and 4.

Differentiation

Support

Give students a simple drawing of the home at 214 Rowancross Lane with the five bottle positions marked along the pipe, so they can match each row of the table to a place. Provide the mean already set up as an addition sentence for item 6.

Extension

Ask students to design a second round of sampling for this fictional home that would test whether the brass faucet fitting is also contributing lead, naming how long the water should sit, how many bottles they would draw, and what result would confirm their idea.

ELL supports

Pre-teach "service line," "stagnation," and "action level" with a labeled cross-section of a street, a yard, and a house. Provide sentence frames such as "Bottle ___ was highest because the water sat in ___." Allow students to point to positions on the drawing when answering items 8 and 10 before writing.

Extensions

Have students look up whether their own water utility publishes a service line inventory, then write three questions a customer could ask about the pipe material between the street main and the house.