Sterling is a very reputable and popular brand in the water softener market. This reputation stems from the wide variety of softeners they offer and the impressive features packed into their products.

The one downside of Sterling’s massive range of softeners is that it can be tricky to research and decide on the right model for your home. So, to simplify your decision-making process, we’ve reviewed every Sterling softener and put together a price guide as well as a list of the pros and cons of each model.

- Type: Ion Exchange
- Grain Capacity: 32,000 – 80,000 grains
- Flow Rate: 11 – 20 GPM
- Warranty: Lifetime

- Type: Template Assisted Crystallization
- Grain Capacity: N/A
- Flow Rate: 15 GPM
- Warranty: Lifetime
Who Makes Sterling Water Softeners?
Sterling water softeners are made by Sterling Water Treatment, founded in 1934 by Charles Sidell and a single employee, Emmitt Culligan. Unlike most water purification companies, Sterling has been manufacturing water treatment products from the very beginning.
This means they have 90 years of experience in the field, and their mission of producing the best water softeners on the market has never changed.
The company is primarily based in Indiana, but there are thousands of licensed contractors in North America that sell Sterling products.

List of Sterling Water Softener Systems
We have a lot of models to review, so we won’t go into too much detail on each one. Instead, we’ll focus on the most distinguishing features of each Sterling water softener system.
We’ll also outline the flow rate, grain capacity, and salt capacity of each Sterling series in a chart below so that you can compare models from different series easily.
FS Series
The Sterling FS Series of water softeners is known for being user-friendly. All of the settings, including regeneration time, can easily be adjusted on the display screen. Models from the FS Series also have an internal battery that ensures the system will continue to work even in the event of a blackout.
FES Series
The FES Series has a backlighted display that’s easy to read even in dark locations, like your basement. The battery is constantly charged and can keep the system running for up to two weeks without power.
FEST Series
The Sterling FEST Series models are similar to the FES series models. However, some of these models come with a higher grain capacity and more salt storage, which makes them capable of softening water with a higher mineral concentration.
FSN Series
Models from the FSN Series specialize in nitrate removal. They’re able to successfully remove nitrate thanks to the nitrate-specific resin that’s found in their tanks.
HEX Series
The HEX Series is known for having a higher kinetic ion exchange resin that results in quicker mineral removal from the water. As a result, these units can produce large volumes of softened water in a relatively short space of time.
INT2
The INT2 Series is known for its minimal salt consumption. Most models can be programmed to use as little as 4 lbs of salt per regeneration cycle, which saves you some money on upkeep costs.
INTX Series
The INTX Series uses a fine mesh ion exchange resin, which results in better iron drawing and water softening capabilities than a lot of other models on this list.
IMX Series
The IMX Series systems use a measurement regeneration system that starts only once a certain amount of water has been softened. However, push-button programming allows you to initiate the process whenever you want or need to.
N Series
The models from the N Series, on the other hand, use a timer that starts the regeneration process at the same time every day. They’re considered to be the most reliable series in the Sterling catalog.
NES Series
The NES Series water softeners are the upgraded version of the N Series, and while they might cost a bit more, their overall grain capacity is higher than the N series.
NESCC Series
The NESCC Series offers the most compact water softeners on the list, which makes them ideal for apartments or households with limited space.
PDIMX Series
The PDIMX Series has water softeners with two tanks that initiate the regeneration process independently. This means that your water is softened around the clock without any delay.
XNT Series
The XNT Series model is a portable water softener. The main difference between this model and the NESCC is that the XNT has a higher overall flow rate.
XTS Series
The XTS Series models have an easy-to-use injector cleaner that keeps the injector free of iron and debris. To use it, all you have to do is push a button.
XTS-HE Series
The XTS-HE Series softeners come with an internal diagnostic system. This system calculates when and how much sodium should be used on the highly kinetic resin to save as much salt as possible.
ZX Series
The ZX Series models feature a chlorine generator that converts a small amount of the brine solution into chlorine. This is then used to disinfect the entire system during each regeneration cycle.
Comparison Table
Comparing so many different water softener models can be challenging simply because there is too much information to fit into one table.
For the sake of simplicity, we’ve only added the most vital stats you need to know before choosing a water softener.
Series | Grain Capacity | Flow Rate | Salt Capacity |
FS | 22.5k – 75k | 6 – 18 GPM | 125 – 300lbs |
FES | 18k – 90k | 6 – 17 GPM | 200 – 600lbs |
FEST | 24k – 29k | 8 – 16 GPM | Not specified |
FSN | Not specified | 5 – 16 GPM | 160 – 220lbs |
HEX | 22.5k – 77.5k | 8 – 25 GPM | 120 – 220lbs |
INT2 | 24k – 30k | 8 – 14 GPM | 150 lbs |
INTX | 24k – 30k | 8 – 18 GPM | Not specified |
IMX | 18k – 75k | 6 – 21 GPM | 120 – 220lbs |
N | 18k – 75k | 6 – 15 GPM | 120 – 220lbs |
NES | 21k – 75k | 6 – 15 GPM | 150 – 200lbs |
NESCC | 24k – 40k | 3 – 12 GPM | Not specified |
PDIMX | 18k – 210k | 6 – 29 GPM | Not specified |
XNT | 24k – 30k | 8 – 18 GPM | Not specified |
XTS | 18k – 75k | 6 – 21 GPM | 125 – 300lbs |
XTS-HE | 16.5k – 77.5k | 6 – 21 GPM | 300lbs |
ZX | 12k – 30k | 16 – 21 GPM | Not specified |

- Type: Ion Exchange
- Grain Capacity: 32,000 – 80,000 grains
- Flow Rate: 11 – 20 GPM
- Warranty: Lifetime

- Type: Template Assisted Crystallization
- Grain Capacity: N/A
- Flow Rate: 15 GPM
- Warranty: Lifetime
Pros & Cons of Sterling Softeners
While the different Sterling series have their own advantages and disadvantages, here we’re interested in the brand overall. Here’s what we like and dislike about it.
PROS
- 5-year and 10-year warranty options: All of the models we mentioned come with 5-year warranty plans for the control valve and the brine tank, while the mineral tank itself gets a 10-year warranty. The tank warranty is pretty standard since most whole-house systems have an expected lifetime of around 10 years. The control valve and brine tank warranties are even better than the industry standard since a lot of models on the market only have a 3-year warranty for those same parts.
- Many models to choose from: Sterling has a lot of different series, and a lot of models in each series. So, it’s easy to find something that would be a good fit for your home, regardless of your requirements. While it might be tough to sort through all the options you have at your disposal, it’ll only take an hour or so.
CONS
- 1-year water conditioner warranty: While the warranties for the conditioner parts are good, the 1-year warranty for the entire unit is pretty short. This essentially means that you’ll need to pay if you have an issue with anything other than the control valve and the tanks after the first year, which isn’t ideal.
Sterling Water Softener Prices
Sterling water softeners cost between $800 and $2,500. This varies depending on the water softener model, size, and specifications.
In my opinion, this pricing is very reasonable. If you have a limited budget, you can always get a portable model that’s a bit cheaper. If not, you can go all out on a two-tank model. It really all depends on whether you have slightly, moderately, or very hard water.
Regardless of your preferences, with Sterling, you’ll likely find a good model for your household needs at a reasonable price.
Is Sterling a Good Water Softener?
All of the Sterling water softeners are good in their own ways. However, with so many to choose from, you need to do your research. The most important thing is to ensure you buy a softener that suits the specific needs of your home.
For example, if your home has very hard water, you’ll need a Sterling system with a high grain capacity. If you live in a large home with high water demands, you’ll need a softener with a high flow rate.
The good news is that with such a wide range of units available, we’re certain you’ll find a Sterling water softener that can meet your exact requirements.