Reading passage Grade 8 Health & Consumer Science

How the Sandoval Family Chose a Home Water Filter

A grade 8 informational passage on home water filters, explaining what carbon and reverse osmosis systems remove, why upkeep matters, and how a family chooses.

Grade: Grade 8
Subject: Health & Consumer Science
Material: Reading passage
Time: 35 min
Prep: No prep
Materials: None

Standards

RI.8.1 Common Core ELA

Cite the textual evidence that most strongly supports an analysis of what the text says explicitly as well as inferences drawn from the text.

How this material aligns: Questions 3 and 6 ask students to cite the passage details that most strongly support inferences about the family's choice and the limits of any filter.

All materials for RI.8.1 →

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: Question 5 has students integrate the passage's prose with the comparison table to name an advantage of two different filter types.

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 identify what carbon and reverse osmosis filters remove from tap water.
Students will infer why filter maintenance matters from evidence in the passage.
Students will explain why the best filter depends on a household's specific needs.

Vocabulary

Activated carbon: Activated carbon is a special charcoal full of microscopic holes that grab and hold chemicals as water flows past. It is the same material used in many home water filter pitchers.
Reverse osmosis: Reverse osmosis cleans water by pushing it through a membrane with holes so tiny that salt and most other dissolved things cannot fit through. It can even turn seawater into fresh water.

Also: membrane, maintenance

Teacher overview

Home water filters are a common consumer purchase, yet many buyers do not know what a given filter actually removes or why it has to be maintained. This passage follows a fictional family through that decision, explaining in plain terms how activated carbon filters and reverse osmosis systems work and why upkeep matters. It pairs with a short comparison table so students can weigh two options side by side before answering.

How the Sandoval Family Chose a Home Water Filter — Grade 8 Health & Consumer Science

Name: ____________________________ Date: ______________

Passage

When the Sandoval family moved into an older house in the town of Greywood, they wanted to know what was in their tap water before deciding how to treat it. Their town's water met every legal limit, but the family still had two concerns. The house had old plumbing that could add lead, and a nearby test had once found PFAS, a group of long-lasting chemicals, in the area's groundwater. Today the lead action level is 15 ppb, dropping to 10 ppb in 2027, and EPA has set a limit of 4.0 ppt each for two common PFAS chemicals, PFOA and PFOS, which water systems must meet by 2029. Those are very small amounts, and no filter removes everything, so the family had to choose a filter suited to their concerns.

They started by learning how filters work. The simplest and cheapest option is an activated carbon filter, the kind found in a pour-through pitcher or attached to a faucet. Activated carbon is full of tiny pores that trap certain molecules as water passes through. Carbon filters are good at reducing the chlorine taste and odor of tap water, and a carbon filter certified for lead can lower lead as well. What carbon does not do well is remove dissolved substances like nitrate or every type of PFAS, so a carbon pitcher alone did not fully answer the Sandovals' worries.

The other option they studied was reverse osmosis, usually installed under the kitchen sink. In reverse osmosis, the home's water pressure pushes water against a thin sheet called a membrane. The membrane has openings so small that water molecules slip through while larger particles, dissolved salts, nitrate, and most PFAS are held back. Reverse osmosis removes the widest range of contaminants of any home option, which is why the Sandovals leaned toward it. It has two costs, though. It is more expensive to buy and install, and it sends some water down the drain as a concentrated leftover stream, so a household uses more water to make its filtered water.

Whatever a family picks, the most important point is about maintenance. Every filter has a cartridge or membrane that fills up over time. A carbon cartridge that is never replaced can stop trapping contaminants and may even release some of what it collected back into the water. A reverse osmosis membrane that is not cleaned or replaced loses its ability to hold particles back. A filter that is not maintained can end up worse than no filter, because the household trusts it while it quietly stops working. The Sandovals wrote the replacement dates on a calendar so they would not forget.

In the end, the family chose a reverse osmosis system for their kitchen tap, because it addressed both the possible lead and the PFAS, and they added a simple carbon pitcher for a second bathroom. No single filter is best for every home. The right choice depends on what a household is trying to remove, what it can afford, and whether it will keep up with the upkeep.

Feature	Carbon pitcher	Reverse osmosis
Main strength	Reduces chlorine taste; some reduce lead	Removes the widest range, including most PFAS and nitrate
Cost	Low	Higher
Water sent to drain	None	Some, as a leftover stream
Upkeep	Replace cartridge often	Replace filters and membrane on schedule

Questions

According to the passage, what is an activated carbon filter good at reducing?
What does the passage say reverse osmosis sends down the drain, and why?
Why did the Sandoval family lean toward reverse osmosis rather than a carbon pitcher alone? Use details from the passage to support your answer.
Using the passage, explain what maintenance means for a filter and why a filter that is never maintained can end up worse than no filter at all.
Using the comparison table, name one advantage of a carbon pitcher and one advantage of reverse osmosis.
The passage says no single filter is best for every home. Based on the passage, what should a family figure out first before choosing a filter?

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: Chlorine taste and odor, and lead if certified for it.
The passage states that carbon filters are good at reducing chlorine taste and odor, and that a carbon filter certified for lead can lower lead.
Answer: A concentrated leftover stream of water.
The passage explains that reverse osmosis sends some water down the drain as a concentrated leftover, so the household uses more water to make its filtered water.
Answer: It removes the widest range, covering both their concerns.
The family worried about lead and PFAS, and the passage says reverse osmosis removes the widest range of contaminants, including most PFAS, which carbon alone does not fully handle.
Answer: Maintenance means replacing the cartridge or membrane on schedule.
The passage says a cartridge that is never replaced can stop trapping contaminants and even release some back, so a neglected filter can be worse than none while the household still trusts it.
Answer: Carbon pitcher: low cost; reverse osmosis: removes the widest range.
The table lists the carbon pitcher's low cost as an advantage and reverse osmosis's ability to remove the widest range, including most PFAS and nitrate, as its advantage.
Answer: What they are trying to remove, their budget, and their upkeep.
The passage's last paragraph says the right choice depends on what a household is trying to remove, what it can afford, and whether it will keep up with the maintenance.

Differentiation

Support

Provide a two-column chart labeled Carbon and Reverse Osmosis for students to fill in as they read, and allow the literal questions to be answered by underlining the supporting sentence in the passage before writing.

Extension

Ask students to write a short paragraph advising a renter who cannot install an under-sink system, using only the passage, and to explain which option that renter should consider and what trade-off they would accept.

ELL supports

Pre-teach activated carbon, membrane, cartridge, and maintenance with simple labeled drawings before reading. Allow students to answer questions 1, 2, and 5 with short phrases or by pointing to the table rather than writing full sentences.