E-Treat® Water Conditioning Anti-Scale System

E-Treat® Water Conditioning Anti-Scale System

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  • Vendor:Watts
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$ 1,999.99
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The Watts E-Treat® Water Conditioning System is an economical and environmentally friendly physical water treatment technology that protects pipes, extends the life of appliances, and provides better tasting water through filtration and conditioning. The E-Treat's dual compartment tank combines the scale prevention capabilities of OneFlow® media and with a high capacity, activated carbon media that is designed to improve water taste by reducing chlorine taste and odor. The OneFlow® treated water enables easier rinsing and reduced water usage in addition to improved taste. The Watts E-Treat® water conditioning system is not a water softener and does not add chemicals or remove minerals, but instead provides an environmentally friendly technology to prevent scale buildup.

Here's how the E-Treat® with OneFlow® media works:

Step #1  Main Tank (Activated Carbon)
Water enters the system and flows down through a two cubic foot bed of coconut shell GAC. This initial water treatment process improves water quality by reducing bad tastes, foul odors, chlorine, and organic substances through adsorption.

Step #2  Inner Tank (Contact Chamber for OneFlow®)
At the same time, water flows upward through the inner tank and through our highly-effective OneFlow® Anti-scale media. the OneFlow® TAC technology pre-emptively attracts hardness minerals and converts them into harmless particles that won't stick to pipes and components.

Installation and Media/Carbon Replacement
E-Treat® water conditioning systems are typically installed where water enters the house for whole house water treatment. Pipe connections are 1" (25mm) in diameter. The anti-scale media is designed to provide a whole house water conditioning for up to three years based on hardness and chlorine levels. We recommend replacing the activated carbon every three years for optimum performance.

Calcium scale in pipes and plumbing equipment often increases energy costs and can lead to expensive repairs to appliances such as hot water heaters, ice machines, coffee makers, and dishwashers. On the other hand, calcium is important to human health, and supplements are often recommended if this important mineral is reduced or absent from a person's diet.

Now there’s a solution for fighting scale and retaining the benefits of calcium in the water – OneFlow®. The same anti-scale technology that’s been used successfully in commercial plumbing is now designed to protect residential appliances in your home. The Watts E-Treat® Water Conditioning System with OneFlow® Media is an excellent system for homes where equipment protection is desired for longer equipment life and reduced energy consumption.


  • Virtually maintenance free – no salt or chemicals to add or maintain
  • Improves efficiency of all water heaters
  • Works to prevent appliance malfunction due to scale build-up
  • Diminishes existing scale problems and costs associated with de-scaling
  • Environmentally friendly alternative to water softeners



  • Compact design for easy installation
  • Easily maintained dual media system
  • No electricity or backwashing required
  • Simple sizing & installation with standard 1" connections
  • Bypass valve included for easy installation and service
  • Long-lasting OneFlow® media change once every three years
  • Two ft3 of High-Capacity activated carbon change once every three years

Click here to download your E-Treat® Anti-Scale Manual.

Feed Water Chemistry Requirements
pH: 6.5 - 8.5
Hardness (maximum): 30 grains (513 ppm CaCO3) *
Water Pressure: 20 psi to 125 psi (1.37 bar to 8.61 bar)
Temperature: 40° F to 100° F (5°C to 38°C)
Free Chlorine: <2 ppm
Iron (maximum): 0.3 ppm **
Manganese (maximum): 0.05 ppm **
Copper: 1.3 ppm ***
Oil & H2S: Must be Removed Prior to E-Treat® System
Total Phosphates: < 3.0 ppm
Silica (maximum): 20 ppm †
TDS: 1500 ppm ††


* Systems using OneFlow® technology are effective at controlling lime-scale formation inside the plumbing system at influent hardness levels up to 30 grains per gallon (513 ppm CaCO3) of calcium carbonate. Due to variances in water chemistry, 30 grains per gallon is a recommended hardness maximum due to potential aesthetic issues related to soft scale residue formation outside of the plumbing system. Testing should be performed to determine proper application where hardness levels exceed 30 grains per gallon.

**Just as with conventional water softening media, OneFlow® media needs to be protected from excess levels of certain metals that can easily coat the active surface, reducing its effectiveness over time. Public water supplies rarely, if ever, present a problem, but if the water supply is from a private well, confirm that the levels of iron (Fe) and manganese (Mn) are less than 0.3 ppm and 0.05 ppm, respectively.

***Pursuant to the EPA drinking water standards, the copper concentration permitted is up to 1.3 ppm. Typically originating from new copper plumbing, high levels of copper can foul OneFlow® media. New Copper lines need to be passivated for a minimum of 4 weeks before placing the unit into service. For applications with copper concentrations greater than 1.3 ppm, please consult Watts Water Quality Technical Service. To further minimize any problem with excess copper, avoid applying excessive flux on the inner surfaces of the pipe and use a low-corrosivity water-soluble flux listed under the ASTM B813 standard.

† OneFlow® media does not reduce silica scaling. While silica tends to have a less significant effect on scale formation than other minerals, it can act as a binder that makes water spots and scale residue outside the plumbing system difficult to remove. This 20 ppm limitation is for aesthetic purposes.

†† All other contaminants must meet the requirements of the USEPA Safe Drinking Water Act. Specific Mineral and Metal MCL's, identified in Watts published Feed Water Chemistry Requirements, supersedes the USEPA SDWA. Water known to have heavy loads of dirt and debris may require pre-filtration prior to OneFlow®.



Inlet / Outlet Connections: 1" FNPT (25 mm)
Nominal Flow Rate: Up to 12 gpm
Maximum Pressure: 125 psi / 8.61 bar
Maximum Temperature: 100°F / 38°C
Minimum Temperature: 40°F / 5°C
Chlorine Reduction: 300,000 Gallons or up to 3 years @ 12 gpm
Scale Prevention: OneFlow Media does not have a grain removal capacity, however, other contaminants present in the water will gradually degrade the effectiveness of this media. Change the OneFlow Media at least once every 3 years.



  • E-Treat® Water Conditioning Treatment System,
    Model: ETREATWCS
  • Two - 1" NPT Threaded Inlet/Outlet Adapters
  • Bypass Valve 
  • Manual

Product Dimensions

    • 13" Dia x 71" H
    • Note: Make sure that the installation location is smooth, level, and sturdy enough to support the weight of the wetted system.

(The overall height and the height of the inlet fitting varies due to material variations and assembly tolerances. Please allow additional clearance above the system for making connections and servicing the system.)

What is OneFlow®?

OneFlow® is an anti-scaling water treatment technology designed to protect plumbing components, pipes, fixtures, valves, fittings, hot water tanks, etc. from the negative effects typically caused by water hardness. OneFlow® is an environmentally friendly alternative to water softening or any other treatment device designed to address scale. OneFlow® prevents scale by transforming dissolved hardness minerals into harmless, inactive microscopic crystal particles. These crystals stay suspended in the water and have a greatly reduced ability to react negatively and form scale compared to untreated hard water.

How does OneFlow® differ from a Water Softener?

OneFlow® uses a specially designed media to convert the dissolved primary hardness mineral (calcium carbonate) into a relatively insoluble microscopic crystal so that it cannot cause harm downstream. A water softener, on the other hand, uses the principles of “ion exchange” to remove calcium and magnesium ions from water while replacing them with sodium ions. A water softener requires a control valve, backwashing, drain line, regeneration, and a brine tank to store salt while OneFlow® requires nothing but an inlet and outlet connection.

Does OneFlow® remove the important minerals in water?

No. OneFlow® preserves the beneficial mineral content while preventing the possible negative scale formation associated with these minerals. By rendering the hardness minerals harmless while still keeping them present, you truly get the best of both worlds. Other treatment methods fall short. In a 2005 report on Nutrients in Drinking Water, the World Health Organization writes, “We conclude that hard water is good because it contains nutrients valuable in themselves…To minimize heart disease risk, the ideal water should contain sufficient calcium and magnesium to be moderately hard."

What factors may affect OneFlow®'s system performance?

Water chemistry and peak flow rate are the guidelines used to assure optimal system performance. Most municipally treated (city) water falls well within our performance guidelines to ensure scale control results. However, there are chemistry limitations related to possible foulants and interference ions. Water known to contain visible dirt and debris must be strained using a wye-pattern strainer or equivalent (100 mesh) before OneFlow® tank systems. More details are available on the product datasheets and IOMs. As with any water treatment technology, correct sizing of the system is important to ensure proper performance. However, OneFlow® is more forgiving of flow variations and unplanned peaks than a conventional water softener.

Does the media in a OneFlow® system need to be replaced?

Yes. Tank-based systems require media replacement every three years. Systems should be installed with this in mind. An isolation valve with a by-pass loop is recommended for most applications so the tank(s) can be taken off-line for media replacement. Filter housing based systems require cartridge replacement every year. Please refer to and follow the instructions in the Installation, Operation & Maintenance manual included with the OneFlow® system.

Are there any application limitations to OneFlow®?

Untreated well water may pose a limitation to OneFlow® due to the unknown chemistry it often possesses. High hardness is never a problem for OneFlow®, but with well water, hardness minerals are often accompanied by other contaminants with levels outside of our operating guidelines. Additionally, closed-loop systems that do not offer a “blow-down” or “flush valve” are not recommended because the micro-crystals need to exit the system.

How easy is it to install a OneFlow® system?

For anyone who has ever installed a Water Pressure Reducing Valve or a Backflow Preventer, installation of a OneFlow® system will be relatively easy. The E-Treat® tank systems offer a 1" “plastic MPT” connection. Several OneFlow® installation accessories are offered to accommodate most applications. OneFlow® systems are compact allowing for easy installation when space is limited. OneFlow's® light-weight makes it easy for the installer to transport with nothing more than a hand truck.

What are the ongoing maintenance costs and considerations for OneFlow®?

One of the great benefits of the OneFlow® technology is the dramatically reduced maintenance requirements. Other than the planned media replacement, there is nothing else required. For tank systems, the media replacement is once every three years, and for filter housing systems, it's once every 2 years. That's it.

Why is OneFlow® a "Green Technology"?

OneFlow® is truly a “Green product” because it saves water and energy in the following ways:

  1. Reduces Energy Consumption – OneFlow® uses no electricity and reduces energy consumption by keeping heat transfer surfaces free of energy-robbing scale formation.
  2. Reduces Chemical or Raw Material Consumption – OneFlow® requires no chemical or significant ongoing consumable (salt, as an example).
  3. Reduces Waste Water Discharge and Water Consumption – Because OneFlow® does not discharge or require backwashing it meets both objectives.
  4. Reduces Space Requirements – OneFlow® systems use approximately 75% less floor space than water softeners.
  5. Retains nature's minerals in the water. The beneficial minerals, calcium & magnesium, are completely retained.
This warranty will be void if defects occur due to failure to observe the following conditions:

  1. E-Treat® systems are warranted for domestic use in residential single-family dwelling applications excluding irrigation water treatment. The use of these systems in light commercial, commercial, or industrial applications will void their limited warranty.
  2. The E-Treat® system must be installed in applications with municipally supplied water adhering to EPA guidelines.
  3. Any component failure must not result from abuse, fire, freezing or other acts of nature, violence, or improper installation.
  4. Equipment must be installed and operated in compliance with the local plumbing codes and on an approved water supply.
  5. Equipment is limited to use at water pressures and temperatures that do not exceed our published specifications.
  6. Water supply must not exceed 3.0 PPM chlorine. For water supply exceeding 3.0 PPM chlorine, pretreatment is required. (Please contact your water treatment specialist.)
  7. Information, including model number, serial number, and date of installation, must be provided for any claims pertaining to equipment in warranty.
  8. Defective parts are subject to inspection by either Watts Regulator Company or any authorized representative before final commitment of warranty adjustment is made.
  9. Watts Regulator Company reserves the right to make changes or substitutions in parts or equipment with material of equal quality or value and of then current production.

To see additional information and details regarding the warranty, please click here to download the manual.

Your Rights Under State Law

Some states do not allow limitations on how long an implied warranty lasts, and some states do not allow the exclusion or limitation of incidental or consequential damages. Therefore the above limitations may not apply to you. This warranty gives you specific legal rights, and you may have other rights that vary from state to state. You should consult applicable state laws to determine your rights. SO FAR AS IS CONSISTENT WITH APPLICABLE STATE LAW, ANY IMPLIED WARRANTIES THAT MAY NOT BE DISCLAIMED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO THE APPLICABLE WARRANTY PERIODS STATED ABOVE.