Lesson plan Grade 10 Health & Consumer Science

First-Draw vs Flushed: Reading a Home Tap Lead Test

A grade 10 health lesson where students interpret a fictional home's first-draw and flushed lead results against the 15 ppb action level and the 10 ppb 2027 level.

Grade: Grade 10
Subject: Health & Consumer Science
Material: Lesson plan
Time: 50 min
Prep: No prep
Materials: Printed Student Handout, Calculator

Standards

HSN-Q.A.1 Common Core Math

Use units as a way to understand problems and to guide the solution of multi-step problems; choose and interpret units consistently in formulas; choose and interpret the scale and the origin in graphs and data displays.

How this material aligns: Students carry parts-per-billion units through each comparison in the handout, computing how far a reading sits above or below the action level and the percent change after flushing.

All materials for HSN-Q.A.1 →

HSA-CED.A.1 Common Core Math

Create equations and inequalities in one variable and use them to solve problems. Include equations arising from linear and quadratic functions, and simple rational and exponential functions.

How this material aligns: Students write and use inequalities in one variable to decide whether a first-draw reading meets the current and future action levels and to find a filter's required removal target.

All materials for HSA-CED.A.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 compare first-draw and flushed lead results to the current and future action levels.
Students will calculate the percent reduction in lead achieved by flushing a tap and by using a certified filter.

Vocabulary

First-draw sample: A water sample taken from a faucet after the water has sat still in the pipes for hours, usually first thing in the morning. It shows how much lead can build up in water that sits in a home's pipes.
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.
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.

Also: flushed sample, parts per billion

Teacher overview

When a home has older plumbing or a lead service line, the lead level at the tap depends heavily on how long the water sat still. A first-draw sample, taken after water rests in the pipes overnight, usually reads higher than a sample taken after the tap runs for a minute or two. This lesson gives students a fictional home's paired results and has them compare each to the lead action level, which is 15 ppb now and drops to 10 ppb in 2027, then reason about what a consumer should do. A common misconception this lesson addresses is that a single low reading proves the water is always safe; the first-draw and flushed pair shows why timing changes the result.

Procedure

Hook (5 min): Ask students what they think happens to water quality when a faucet is not used all night. Collect a few predictions about whether metals in the pipe build up in the standing water, then tell them a fictional family tested this directly.

Direct instruction (12 min): Explain first-draw versus flushed sampling and why the action level is a system trigger for treatment, not a bright line between safe and unsafe. Model one comparison: given a reading and the 15 ppb action level, subtract to find how far above or below it sits, keeping the ppb unit attached. Frame the coming 10 ppb level as a rule in motion that will make more homes' results matter.

Guided practice (13 min): With the class, work one paired example for a fictional home reading 22 ppb first-draw and 5 ppb flushed, computing the difference from each action level and the percent reduction from flushing, so students rehearse the method before independent work.

Independent practice (15 min): Students complete the Student Handout for the fictional Petrakis family and a neighbor, comparing readings to both action levels, computing percent reductions, and identifying reasonable consumer steps.

Closure and exit ticket (5 min): Students answer on a card: "A first-draw reading of 14 ppb is below the current 15 ppb action level. Explain in one sentence why it could still concern a family in 2027." Collect and check that students connect the reading to the lower future level.

First-Draw vs Flushed: Reading a Home Tap Lead Test — Grade 10 Health & Consumer Science

Name: ____________________________ Date: ______________

Student Handout

All results below are invented for this fictional scenario. The lead action level is 15 ppb now and drops to 10 ppb in 2027.

The fictional Petrakis family lives in an older home in Glenmoor. Their first-draw sample reads 18 ppb. After running the cold tap for two minutes, the flushed sample reads 4 ppb.

By how many ppb does the 18 ppb first-draw reading exceed the current 15 ppb action level?
By how many ppb does the 18 ppb first-draw reading exceed the 2027 action level of 10 ppb?
Does the flushed sample of 4 ppb meet both the current and the 2027 action levels?
Find the percent reduction in lead from first-draw to flushed, from 18 ppb down to 4 ppb.
A neighbor's first-draw reads 12 ppb. Compared with the 2027 action level of 10 ppb, how many ppb higher is it?
List two reasonable steps the Petrakis family could take given an 18 ppb first-draw result.
EPA estimates that about 4 million lead service lines still remain across US water systems. Explain why the first-draw result matters most in an older home like this one.
A certified filter is rated to remove at least 90 percent of lead. Applied to the 18 ppb first-draw water, what is the highest level that could remain?

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

Answer Key

All readings below refer to the fictional Petrakis family scenario.

Answer: 3 ppb.
The first-draw is 18 ppb and the current action level is 15 ppb: 18 - 15 = 3 ppb above.
Answer: 8 ppb.
Against the 2027 level of 10 ppb: 18 - 10 = 8 ppb above, so the same water is 3 ppb over today's line and 8 ppb over the future one.
Answer: Yes.
The flushed reading of 4 ppb is below 15 ppb and also below 10 ppb, so it meets both the current and future action levels.
Answer: about 78 percent.
The drop is 18 - 4 = 14 ppb. As a share of the starting value: 14 / 18 x 100 = 77.8, which rounds to about 78 percent.
Answer: 2 ppb.
The neighbor's 12 ppb first-draw is below today's 15 ppb line but 12 - 10 = 2 ppb above the 2027 action level.
Answer: Flush before use and add a certified filter.
Reasonable steps include running the tap before drawing water for drinking or cooking, using a filter certified for lead, and asking the utility whether the home is served by a lead service line.
Answer: Standing water picks up lead from old pipes.
In an older home, water that sits overnight in lead-bearing faucets, solder, and pipes has the most contact time, so the first-draw sample captures lead from the plumbing nearest the tap. Where a lead service line is present, water that sat in the service line arrives a little later, which is why the updated federal rule also requires a fifth-liter sample at those homes.
Answer: 1.8 ppb.
Removing at least 90 percent leaves at most 10 percent: 18 x 0.10 = 1.8 ppb remaining, which is below both action levels.

Differentiation

Support

Provide a number line marked at 10 ppb and 15 ppb so students can place each reading visually before subtracting. Pre-fill question 1 as a worked model, and allow a calculator for the percent-reduction step.

Extension

Ask students to write a general inequality for the filtered result of any first-draw reading r, using at least 90 percent removal, and determine the largest first-draw reading that a 90-percent filter could bring to the 2027 action level of 10 ppb or below.

ELL supports

Pre-teach "first-draw," "flushed," and "action level" with a labeled picture of a faucet, a full pipe overnight, and a running tap. Allow questions 3, 6, and 7 to be answered with short phrases or a labeled sketch.