iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD

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Product guide

iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD

The iSpring PH100 is a six-stage under-sink reverse osmosis water filtration system with an alkaline remineralization stage. Its listing claims 100 GPD capacity and a 1:1 pure-to-waste ratio, making it a fit for buyers seeking filtered drinking water with minerals restored after RO filtration.

At a glance

Six-stage RO configuration adds an alkaline remineralization filter that the listing says restores minerals removed during reverse osmosis.
The listing claims 100 GPD capacity and a 1:1 pure-to-waste water ratio.
Described as fitting under a standard kitchen sink, with a brushed nickel all-metal faucet claimed in the feature text.

Price

$305.49Save 15%

Reference price: ~~$359.99~~

Price checked: Nov 14, 2026

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Often bought together

iSpring F9K NSF Certified 1-Year Reverse Osmosis Water Filter, Alkaline Remineralization Filters for 6-Stage RO Systems, Without RO Membrane

$69.24

iSpring ICEK Ultra Safe Fridge Water Line Connection and Ice Maker Installation Kit for Reverse Osmosis RO Systems & Water Filters, 1/4", 20 feet

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Pros and cons

Pros

The separate remineralization stage addresses buyers who prefer minerals restored after RO filtration.
The stated 1:1 pure-to-waste ratio gives buyers a clear water-use figure to compare with other systems.
Manufacturer says the system includes US-made filters and provides installation instructions and videos.

Cons

Installation requires fitting an under-sink system and its tubing, rather than simply attaching a filter to an existing faucet.

Technical specifications

8 specifications

Identity
Brand	iSpring
Model	PH100

Filtration and claimed performance
Stages	6-Stage
Rated capacity	100 GPD
Pure-to-waste ratio	1:1

Dimensions and installation
Weight listed	0.27 g
Installation location	Under sink

Materials
Material listed	Acrylonitrile Butadiene Styrene (ABS), Plastic, Polyethylene (PE), Polypropylene (PP), Polystyrene

What to know before buying

Listing details to confirm

Manufacturer performance and contaminant-removal statements are claims, not independently verified measurements. The listing also says 100 GPD and 1:1 pure-to-waste ratio, while describing installation as typically taking a couple of hours. Customer feedback includes reports of small leaks, so careful setup and leak checks matter.

What’s in the box

Included

Housings
Filters
Parts
Tubings
Faucet
Mounting bracket

Who is it for?

A good fit for

Households wanting an under-sink RO setup with an added remineralization stage.
Buyers comparing systems by stated daily output and pure-to-waste ratio.
People prepared to install tubing, filters and a dedicated faucet under the sink.

Less suited to

Buyers seeking a countertop or faucet-mounted filter with minimal installation.
Anyone requiring independently verified contaminant-removal results from the supplied information.

iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.5 / 5 · 341 ratings

5 stars80%80%
4 stars8%8%
3 stars4%4%
2 stars2%2%
1 star6%6%

Customer feedback highlights crisp-tasting water, favorable installation experiences and reports of good day-to-day operation. Some users also report small leaks. These are customer perceptions rather than proof of filtration performance. The reported leak concern is particularly relevant for an under-sink system with tubing and fittings, while the positive taste comments align with the product’s intended drinking-water use and its listed remineralization stage.

Positive themes

Customers report good-tasting, crisp water.
Feedback describes installation as easy, including a report that the unit arrived partly assembled.
Some customers report that the system worked well after a month of use.

Negative themes

Some customers report small leaks.

Mixed feedback

Customer feedback includes positive comments about perceived water quality and value, alongside leak concerns.

Frequently asked questions

What type of filtration system is the iSpring PH100?

It is described as a six-stage under-sink reverse osmosis system with an alkaline remineralization stage.

What are its listed capacity and pure-to-waste ratio?

The title and feature text claim 100 GPD and a 1:1 pure-to-waste water ratio.

Does the system include a faucet?

The manufacturer’s included-components list names a faucet and mounting bracket. The feature text describes the faucet as brushed nickel and all-metal.

What should buyers know about installation?

The listing describes do-it-yourself installation, quick-fitting tubing connections and a typical installation time of a couple of hours. Customer feedback also mentions some small leaks, so check connections for leaks after installation.