Compare water treatments
A plain-English comparison of testing, softeners, filters, reverse osmosis, UV and targeted treatment. No single technology handles every water concern.
General information, not a treatment recommendation. For health questions about a test result, speak to a certified lab or your local board of health.
| Option | What it helps with | What it does not fix | Where it goes | Upkeep | Test first? |
|---|---|---|---|---|---|
| Water testing: the first step | Measures the substances included in the test panel and provides a starting point for discussing equipment. | Testing does not treat water. A result covers the submitted sample and analyses, not every tap or every possible substance. | Samples from a tap or water system, following the laboratory’s collection instructions. | Follow the laboratory or local board of health’s guidance on follow-up samples; there are no filters, salt or bulbs in a laboratory test. | Testing is the starting point. Ask what the panel includes. |
| Water softeners | Reduces hardness minerals, mainly calcium and magnesium, associated with scale and poor soap lather. | Not a disinfection system. An ordinary softener is not a PFAS-removal system, and other contaminant claims must be checked for the specific model. | Typically at the water entry point to serve household plumbing; the installation determines which lines are treated. | Salt or regenerant replenishment for salt-based units, regeneration and servicing according to the manufacturer. | Yes. A hardness measurement and the intended use help define the scope. |
| Whole-house filtration: sediment and carbon | Sediment stages capture particles. Carbon can improve taste and odor and may reduce specific chemicals, depending on the product. | Sediment filtration does not remove dissolved hardness. A general taste-and-odor claim does not establish PFAS, arsenic or germ reduction. | At the point where water enters the home; a single-tap filter is a separate point-of-use installation. | Cartridge or media replacement, and any backwashing or other servicing specified for the unit. | Yes. The filter media and any reduction claims should match the measured issue. |
| Reverse osmosis (RO) | A membrane separates some dissolved substances from water. Which contaminants are reduced depends on the complete system and its claims. | Does not remove every inorganic or organic contaminant. A single-tap unit does not treat every household tap, and the process produces reject water. | Commonly a point-of-use installation, such as a dedicated kitchen tap. | Pre-filter, post-filter and membrane replacement, plus tank and other servicing required by the manufacturer. | Yes. Incoming-water results and the model’s specific reduction claims matter. |
| UV treatment | Uses ultraviolet light for disinfection of microorganisms when the unit and incoming-water conditions are suitable. | Does not remove chemicals such as arsenic or PFAS, and does not remove hardness minerals. | A treatment chamber may serve a whole-house line or a particular use point, depending on the installation. | UV lamp/bulb, sleeve and any pre-filter servicing according to the unit’s instructions. | Yes. Results and incoming-water conditions inform the system design and any pre-filtration. |
| Targeted arsenic treatment | Arsenic-specific adsorptive media, anion exchange or suitable RO can reduce arsenic under the conditions described for the system. | Arsenic form and other water chemistry affect performance. Do not assume a general filter or an RO unit addresses every form of arsenic. | Single-tap or whole-house approaches, depending on the selected technology and design. | Media/cartridge or membrane replacement and any pre-treatment servicing for the selected system. | Yes. A lab can explain arsenic testing and whether its form needs additional analysis. |
| Targeted PFAS treatment | PFAS-specific granular activated carbon, ion-exchange media or suitable RO can reduce PFAS; performance depends on the device and conditions. | A standard sediment filter or softener is not PFAS treatment. A certification label is not a blanket guarantee for every PFAS or current regulatory level. | Point-of-use or whole-house designs, depending on the device and installation. | Media, cartridge or membrane replacement, performance sampling and appropriate handling of spent media or reject water. | Yes. MassDEP discusses testing before installation and follow-up testing after treatment. |
| Targeted radon-in-water treatment | Whole-house aeration can remove radon from water and vent the gas outside; granular activated carbon can also capture radon. | This is not general PFAS treatment. Carbon used for radon can accumulate radioactive materials and raises handling and disposal considerations. | MassDEP describes a whole-house aeration system at the water entry point. | Aeration equipment servicing or specialist management of carbon/media, as specified for the design. | Yes. A radon-in-water result is relevant to the treatment design and any carbon stage. |
Water testing: the first step
A basic in-home dealer assessment and a certified laboratory analysis are different services. A lab can explain its available analyses and collection requirements. For health questions about a result, speak to a certified lab or your local board of health.
Sources: CDC: About Choosing Home Water Filters · MassDEP: Find a Certified Laboratory for Water Testing
Water softeners
A softener is a specific type of mineral treatment, not a catch-all filter. EPA describes water and salt use during regeneration. Ask the installer about maintenance and any local requirements for discharge.
Sources: CDC: About Home Water Treatment Systems · EPA WaterSense: Guide to Selecting Water Treatment Systems (PDF) · MassDEP: Homeowner Guidance for Removing PFAS from Private Drinking Water Wells (May 2024 PDF, hosted by Dover)
Whole-house filtration: sediment and carbon
Sediment and carbon are different stages with different jobs. Check the exact product’s performance data and certified reduction claims rather than assuming every whole-house filter handles the same substances.
Sources: CDC: About Choosing Home Water Filters · EPA WaterSense: Guide to Selecting Water Treatment Systems (PDF) · MassDEP: Homeowner Guidance for Removing PFAS from Private Drinking Water Wells (May 2024 PDF, hosted by Dover)
Reverse osmosis (RO)
CDC and EPA describe RO as one treatment technology, not a universal solution. In Massachusetts, wastewater and discharge requirements also need consideration; the MassDEP PFAS FAQ explains restrictions that may apply. Ask the installer or relevant authority about the proposed discharge route.
Sources: CDC: About Home Water Treatment Systems · EPA WaterSense: Guide to Selecting Water Treatment Systems (PDF) · MassDEP: PFAS in Private Well Drinking Water Supplies FAQ, including radon and carbon treatment
UV treatment
CDC notes that UV systems work better with pre-filtration. EPA distinguishes UV disinfection from chemical removal. MassDEP’s maintenance guidance describes the lamp and quartz sleeve; follow the instructions for the particular unit rather than assuming one maintenance schedule fits all.
Sources: CDC: About Home Water Treatment Systems · EPA WaterSense: Guide to Selecting Water Treatment Systems (PDF) · MassDEP: Homeowner Guidance for Removing PFAS from Private Drinking Water Wells (May 2024 PDF, hosted by Dover)
Targeted arsenic treatment
MassDEP distinguishes arsenic 3 from arsenic 5 and explains that some treatment designs need additional preparation of the water. This page does not select a process or provide dosing instructions. Discuss the laboratory results, equipment scope and maintenance with a qualified provider.
Targeted PFAS treatment
MassDEP explains why product-specific performance, continuing maintenance and wastewater requirements matter. This comparison does not promise a removal percentage or that a particular device meets a drinking-water limit.
Sources: MassDEP: PFAS in Private Well Drinking Water Supplies FAQ, including radon and carbon treatment · MassDEP: Homeowner Guidance for Removing PFAS from Private Drinking Water Wells (May 2024 PDF, hosted by Dover)
Targeted radon-in-water treatment
MassDEP discusses radon when evaluating PFAS carbon treatment and describes aeration before carbon in some systems. A water-treatment listing does not establish expertise in indoor-air radon systems. Ask about the exact scope and professional maintenance requirements.
Sources: MassDEP: PFAS in Private Well Drinking Water Supplies FAQ, including radon and carbon treatment
Questions about treatment comparisons
Does one water treatment fix every problem?
No. CDC and EPA describe different technologies for different substances and conditions. A product’s own reduction claims, installation scope and maintenance requirements matter. See the sources listed on this page.
What is the difference between whole-house and one-tap treatment?
A whole-house or point-of-entry system treats water as it enters the building. A point-of-use system serves a particular tap or use point. Treating one tap does not treat all water throughout the home.
Does this page tell me whether my water is safe?
No. It is a general comparison of equipment types, not a safety certification or a treatment recommendation for your home. For health questions about a test result, speak to a certified lab or your local board of health.
Are prices or removal percentages shown here?
No. This guide does not provide price estimates or promise a removal percentage. Ask providers for a written quote covering installation, ongoing consumables, servicing and any follow-up testing.
Sources
- CDC: About Home Water Treatment Systems
- CDC: About Choosing Home Water Filters
- EPA WaterSense: Guide to Selecting Water Treatment Systems (PDF)
- MassDEP: Arsenic in Private Well Water FAQs
- MassDEP: PFAS in Private Well Drinking Water Supplies FAQ, including radon and carbon treatment
- MassDEP: Homeowner Guidance for Removing PFAS from Private Drinking Water Wells (May 2024 PDF, hosted by Dover)
- MassDEP: Find a Certified Laboratory for Water Testing
Capabilities depend on the specific product, water conditions and maintenance. Source descriptions are not a guarantee for every model.