Home water treatment device: 5 checks before you buy
Dewgate Editorial Team ·
Before buying a home water treatment device, confirm the concern or test result first, then check the device's registration and certified contaminant. California State Water Resources Control Board notes that if you are thinking of buying a home water treatment device, you are probably concerned about your drinking water.
Key takeaways before buying
- Check if you actually need a device: According to the Minnesota Department of Health, most Minnesotans do not need to install water treatment at home to protect their health.
- Remove the source first: If you know your drinking water is contaminated or are concerned about its color, taste, or odor, the Minnesota Department of Health advises first trying to remove the source(s) of contamination or replace the contaminated water supply with a safer supply.
- Search the registered device database: The California State Water Resources Control Board maintains a searchable database of all currently registered devices, allowing you to verify a product's status before purchase.
- Verify the specific contaminant form: Many water treatment devices are certified to reduce Arsenic 5 but may provide a minimal reduction of Arsenic 3, so you must match the device's certification to your specific test result ( California State Water Resources Control Board).
- Confirm your home's supply pressure: A water supply pressure of at least 40 psi is required for effective operation, as noted by the California State Water Resources Control Board.
Before you shop: is treatment needed and what do the tests say
Start by asking whether treatment is actually required for your specific water situation. The Minnesota Department of Health states that most Minnesotans do not need to install water treatment at home to protect their health. If you know your drinking water is contaminated or you are concerned about the color, taste, or odor of your water, first try to remove the source(s) of contamination or replace the contaminated water supply with a safer supply. If this source removal is not possible, home water treatment may be appropriate. Use the Minnesota Department of Health resource to help decide if home water treatment makes sense for you and what treatment options may be best for you. The page also directs readers to find information about treating specific contaminants and different treatment devices in the Home Water Treatment PDF, starting on page 3.
If you notice obvious stains, tastes, or odors in your water, seek testing that will help identify the source of these symptoms, according to Penn State Extension. Do not assume a device will fix an unidentified issue; the goal of testing is to pinpoint the cause so you can address the root problem rather than just filtering the symptom. For a related check, see Check a water meter for leaks: 6 official guides.
| Step | Action | Source |
|---|---|---|
| 1 | Confirm if treatment is needed for your health | Minnesota Department of Health |
| 2 | Attempt to remove the contamination source first | Minnesota Department of Health |
| 3 | Seek testing to identify the source of stains or odors | Penn State Extension |
While comparing devices: registration and contaminant claims
Open the California State Water Resources Control Board Residential Water Treatment Devices page to access the searchable database of all currently registered devices. This tool lets you filter options by treated contaminants, system type, manufacturer name, or device name and model number. Assembly Bill 119 was signed into law in 2013, making significant changes to the Water Treatment Device Program, and the statute's major provisions became effective January 1, 2014.
When your lab results show arsenic, look closely at the specific form listed. Many water treatment devices are certified to reduce Arsenic 5 but may provide a minimal reduction of Arsenic 3. Arsenic 3 is much more difficult to remove from the water. A device label that does not specify the form may leave you with a filter that performs poorly against the variant present in your supply.
| Search Parameter | Example | Source |
|---|---|---|
| Treated contaminant | Lead, Arsenic, or PFOA/PFOS | California State Water Resources Control Board |
| System type | Refrigerator filter or whole home/point-of-entry | California State Water Resources Control Board |
| Manufacturer or model | Manufacturer name or device name/model number | California State Water Resources Control Board |
Search the database by the exact contaminant from your test report before comparing prices. If your results identify Arsenic 3, verify that the specific model you are considering is certified for that form, not just Arsenic 5.
At purchase: operating conditions and limits
Before you pay, verify that your home's plumbing matches the conditions the device was tested under. The California State Water Resources Control Board outlines nitrate levels and a water pressure requirement for treatment. If your supply falls outside these ranges, the device may not perform as advertised.
| Condition | Limit or Requirement | Source |
|---|---|---|
| Nitrate level (as NO3) | Less than or no more than 108 mg/l | California State Water Resources Control Board |
| Nitrate level (as N) | Less than or no more than 24 mg/L | California State Water Resources Control Board |
| Water supply pressure | At least 40 psi | California State Water Resources Control Board |
According to California State Water Resources Control Board, treatment is generally acceptable for nitrates at levels of less than or no more than 108 mg/l of nitrate measured as NO3. The same source notes that 24 mg/L of nitrate measured as N is also an acceptable ceiling. If your recent lab test shows a nitrate level above these numbers, the device may not be suitable for your specific water quality.
Pressure is just as critical. The California State Water Resources Control Board states that water supply pressure of at least 40 psi is required for effective operation. Check your home's pressure with a gauge attached to an outdoor spigot or hose bib. If your pressure is below 40 psi, the device may not filter correctly, regardless of the contaminant level.
If you are still determining whether you need a device, consider the cost of confirming your water quality first. Many certified labs in Washington perform lead tests for $25 to $50 each, according to Washington State Department of Health. This cost is for the testing service, not the device itself. Knowing your exact contaminant levels and home pressure ensures you buy a device that actually fits your situation. For other home purchases, see Water saving home upgrades: 5 steps to plan purchases.
Illustrative example: arsenic result and home pressure
Suppose your home's lab report identifies Arsenic 3. A device label says it is certified to reduce Arsenic 5. Because many devices may provide only a minimal reduction of Arsenic 3, you search the registered-device database for an Arsenic 3 listing before comparing prices. Next, you attach a gauge to an outdoor spigot and read 30 psi. Since at least 40 psi is required for effective operation, your pressure falls short of that requirement, so you confirm the device's operating conditions before buying anything.
Treatment device reference table
The table below summarizes the guidance available from each publisher for verifying water treatment needs and device registration.
| Publisher | Key Guidance | URL |
|---|---|---|
| Minnesota Department of Health | Most Minnesotans do not need to install water treatment at home to protect their health. | ( Minnesota Department of Health) |
| California State Water Resources Control Board | The Residential Water Treatment Device Registration Program now has a searchable database of all currently registered devices. | (California State Water Resources Control Board) |
| Penn State Extension | If there are obvious stains, tastes, or odors in water, seek testing that will help identify the source of these symptoms. | ( Penn State Extension) |
| Washington State Department of Health | Many certified labs in Washington perform lead tests for $25 to $50 each. | ( Washington State Department of Health) |
Use this table to cross-reference your specific water quality concerns with the available public resources.
What each check prevents
Each check targets a specific gap between a device label and your actual water. The table below maps the five checks to the risk each one prevents, using only the rules stated by the named sources.
| Check | Risk Prevented | Source |
|---|---|---|
| Confirm treatment need | Buying a device when the source can be removed or replaced | Minnesota Department of Health |
| Lab test before buying | Treating the wrong contaminant or an unknown issue | Penn State Extension |
| Registration database lookup | Purchasing a device not registered for your system type | California State Water Resources Control Board |
| Treated contaminant claim | Assuming certification for Arsenic 5 covers Arsenic 3 | California State Water Resources Control Board |
| Operating conditions at home | Ineffective operation due to low supply pressure | California State Water Resources Control Board |
The first check prevents the error of installing a treatment system when a safer supply or source removal is possible. The Minnesota Department of Health advises that if you know your drinking water is contaminated or are concerned about color, taste, or odor, you should first try to remove the source(s) of contamination or replace the contaminated water supply with a safer supply. If this is not possible, then home water treatment may be appropriate.
The second check prevents treating the wrong contaminant. If you notice stains, tastes, or odors, testing can help identify the source of these symptoms. Without this data, you may buy a device that does not address the actual contaminant present in your water.
The third check prevents buying a device that is not registered for your specific system type. The California database allows searches by treated contaminant, system type, manufacturer, or model. This lookup lets you filter devices by system type.
Write down the contaminant and test date you are acting on, then search the registered-device database for that contaminant before you spend anything.
FAQ: buying a home water treatment device
What should I check before buying a home water treatment device?
Confirm the concern or test result first, then ask whether the source of contamination can be removed. After that, check the device's registration and the specific contaminant it is certified to reduce. Minnesota Department of Health notes that most Minnesotans do not need to install water treatment at home to protect their health.
Does a registered device mean my water is safe?
Registration indicates the device is certified for specific contaminants under the California program, but it does not guarantee your specific water is safe without testing. The California State Water Resources Control Board maintains a searchable database of all currently registered devices. This database lists devices by treated contaminant, system type, manufacturer, or model, but it does not decide if your particular water supply is safe.
How much does a lab test cost?
Many certified labs in Washington perform lead tests for $25 to $50 each. Washington State Department of Health provides this cost range for certified laboratories. This figure is for lead testing, the subject of that page.
Why does the form of arsenic matter on a device label?
Arsenic 3 is much more difficult to remove than Arsenic 5. Many devices are certified to reduce Arsenic 5 but may provide only minimal reduction of Arsenic 3. The California State Water Resources Control Board highlights this difference in certification. Check the specific form of arsenic your water contains before relying on a device's general certification.