Reading passage Grade 4 Science
How Millhaven Knows Its Water Is Safe to Drink
A grade 4 informational passage following a fictional lab analyst who tests water at four points from river to tap.
Objectives
- Students will identify the four points along a water system where a lab analyst tests samples.
- Students will explain why testing water at multiple points helps identify where a problem started.
- Students will write a short informative paragraph sequencing the water's path from river to tap.
Vocabulary
- Raw water
- Raw water is water taken from a river, lake, or well before it has been treated. It may look clean, but it is not ready to drink yet.
- 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: filter, disinfectant
Teacher overview
This original passage follows a fictional water quality lab analyst named Priya through her daily testing routine at the Millhaven Water Treatment Plant, where she checks samples at four separate points instead of only once at the end. Many students assume water is tested a single time before it reaches a home, so the passage explains why testing at each stage (the river, after filtering, after disinfecting, and out at a distant tap) lets a problem be traced back to exactly where it started. The comprehension questions move from locating stated details to drawing inferences, matching the two halves of RI.4.1, and a short closing writing task lets students practice sequencing information for W.4.2.
Passage
Testing the Water, Step by Step
Before a glass of water reaches a tap in Millhaven, workers test it again and again. At the Millhaven Water Treatment Plant, a lab analyst named Priya checks water at four different spots. She does not just test it once at the end.
The first sample comes straight from the river. This is before any treatment starts. Priya calls this the raw water sample. She checks how cloudy it looks. She also checks for a strange smell or an odd color. This sample shows what kind of day the river is having. Rain and melting snow can change the river fast.
The second sample comes after the water passes through big filters. The filters are packed with layers of sand and gravel. Filtering removes tiny bits that make water look cloudy. This sample should look much clearer than the first one. If it does not, something in the filters needs fixing.
The third sample comes after the plant adds a disinfectant. This step kills germs that could make people sick. Priya checks how much disinfectant is left in the sample. Too little would not protect people. Too much would make the water taste strange.
The fourth sample comes from a tap far out in town, at a school on the edge of Millhaven. This sample tells Priya if the water is still clean. It has traveled a long way through pipes under the streets.
Priya explained why she checks all four spots, not just the last one. If a problem showed up only in the final sample, she would not know what caused it. Testing at each step lets her trace a problem back fast. It might have started at the river, in the filters, during disinfecting, or in the pipes.
Every result goes into a logbook. The plant keeps this logbook for years. State inspectors can check it at any time. It proves the plant tests often and that the water has stayed safe. Testing is not a one-time job at Millhaven. It happens every day, sample after sample, long before anyone turns on a tap.
Questions
Name the four spots where Priya tests the water.
What does the raw water sample tell the plant?
Why does Priya check how much disinfectant is left in the third sample?
Why does Priya also test water at the school tap, not just after the disinfecting step?
Use details from the passage. Why does testing at all four spots help Priya more than testing only the last sample?
Why do you think state inspectors want to check Millhaven's logbook?
Writing task. In one paragraph, explain how water travels from the Millhaven River to a kitchen tap and gets tested along the way. Use at least three details from the passage, in the order that they happen.
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: The river, after filtering, after disinfecting, and a tap in the distribution system.
These four points are named in order across the passage's second through fifth paragraphs.Answer: What kind of day the river is having.
The passage states that rain and melting snow can change the river fast, so the raw water sample tells the plant about current river conditions.Answer: So the water has enough disinfectant to protect people, but not so much that it tastes strange.
Stated directly in the passage: too little would not protect people, and too much would make the water taste strange.Answer: To check whether the water is still clean after its long trip through the pipes.
The passage states that the fourth sample tells Priya whether the water is still clean by the time it finishes traveling through the pipes under Millhaven's streets, which the disinfection sample alone could not show.Answer: Testing at each stage lets Priya trace a problem back to its source quickly.
The passage states that if a problem showed up only in the final sample, Priya would have no way to know which step caused it, but testing at every stage shows exactly where a problem started.Answer: Answers will vary.
A strong answer connects the logbook review to accountability, such as inspectors wanting proof that the plant tests often enough and that the water has actually stayed safe over time, not just on the day of an inspection.
Writing task exemplar. Before it reaches a kitchen tap, water in Millhaven starts as a raw sample taken straight from the river, which tells the plant how clean the river is that day. After the water passes through sand and gravel filters, a second sample checks that filtering has made it noticeably clearer. Once the plant adds a disinfectant to kill germs, a third sample confirms there is enough disinfectant to protect people without making the water taste strange. Finally, a fourth sample taken from a tap at a school on the edge of town confirms the water is still clean after its long trip through Millhaven's underground pipes.
Differentiation
Support (below grade level)
Read the passage aloud once before students reread it independently, and provide a simple four-box sequence chart (River → Filters → Disinfectant → Distant tap) for students to fill in before answering the questions. Reduce the question set to questions 1, 2, and 3.
Extension (above grade level)
After question 6, ask students to research (using a teacher-provided source, not open internet search) what a "boil water notice" is and why a plant might issue one if a test at any of the four points showed an unexpected result.
ELL supports
Pre-teach raw water, filter, disinfectant, and distribution system with a simple diagram showing the four testing points in order along a line from river to tap. Allow students to answer questions 1 through 3 with short phrases pointed to directly in the text rather than full sentences.