# 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.

- [Original product page](https://best-deals.pro/product/ispring-ph100-alkaline-under-sink-ro-system)
- [View offer](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- Market: US
- Language: en-US
- Currency: USD
- Brand: iSpring
- Model: PH100
- Category: Home & Kitchen > Kitchen Appliances > Water Purifiers
- Price: 305.49 USD
- Previous price: 359.99 USD
- Discount: 15%
- Price checked: 2026-11-14T07:05:43.819Z
- Rating: 4.5 / 5
- Reviews: 341

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## 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.

## 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.

## 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

## Before you buy

- 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.

## In the box

- Housings (Included)
- Filters (Included)
- Parts (Included)
- Tubings (Included)
- Faucet (Included)
- Mounting bracket (Included)

## 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.

## Customer feedback

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.
- Positive themes: Feedback describes installation as easy, including a report that the unit arrived partly assembled.
- Positive themes: 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.

## Alternative options

- [iSpring RCC7-BN NSF Certified, High Capacity Under Sink 5-Stage Reverse Osmosis Water Filter, RO Drinking System, 75 GPD Brushed Nickel Faucet, Patented Top-Mounted Faucet Design for Easy Installation](https://best-deals.pro/visit/ispring-rcc7-bn-5-stage-under-sink-ro-system)
- [iSpring RCC7P-AK, 6-Stage Reverse Osmosis System Under Sink Alkaline Water Filter and Pump, RO Drinking Water Filtration System, Patented Top-Mounted Faucet Design for Easy Installation](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [iSpring RO500AK-ORB Reverse Osmosis Water Filter, 500 GPD with Alkaline \| Under Sink Tankless RO Water Filter, Fill 8 oz in 10 s, 2:1 Low Drain Ratio, TDS PFAS Reduction, Auto Flush, Filter Reminder](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [3M Aqua-Pure Under Sink Reverse Osmosis Water Filtration System 3MRO301 \| Compact RO System Reduces Impurities For Clean Drinking Water](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [Bluevua RO100ROPOT-Lite Countertop Reverse Osmosis Water Filter \| 3:1 Pure to Drain Ratio, Portable RO Filtration with Remineralization, WQA & NSF Certified](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [iSpring RO5004F Reverse Osmosis Water Filter with UV, SGS Tested PFAS and TDS Reduction, 500 GPD RO System Under Sink, 2:1 Pure to Drain, Tankless RO Water Filtration System, Filter Life Monitor](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [iSpring WCFM400K Whole House Iron and Manganese Water Filter System, Digital Control with Automatic Regeneration & Air Injection, Set & Forget Design](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [iSpring RCC7AK-UV, NSF 58&372 Certified, 7-Stage Reverse Osmosis Water Filter System with Alkaline and LED UV Filter, Patented Top-Mounted Faucet Design for Easy Installation](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [Waterdrop T4-A Alkaline Mineral Tankless Reverse Osmosis System, Dual Flow \| NSF/ANSI 372 Certified, 10-Stage, 450 GPD Under-Sink RO Filtration System, 2:1 Pure to Drain, BPA Free, Plug-in required](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [iSpring RO500AK Alkaline Reverse Osmosis System, NSF 58 Certified, 500 GPD \| Under Sink Tankless RO Water Filter, Fill 8 oz in 10 s, 2:1 Low Drain Ratio, TDS PFAS Reduction, Auto Flush, Filter Reminder](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [Frizzlife S800 Non-Electric Tankless Reverse Osmosis Water Filter \| Smart WiFi App Control, 900GPD Alkaline Mineral pH+ RO Water Filtration System, 4:1 Pure to Drain, NSF/ANSI 58 & 372 Standard](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [Aquasana Water Filter for Sink Faucet \| Claryum Direct Connect \| AQ-MF-1 \| Reduces Lead, PFAS, Chlorine, Bad Taste & Odor \| WQA Certified \| For Existing Faucet \| 784 Gal \| 1-Year Warranty](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)

## Add-ons

- [iSpring F9K NSF Certified 1-Year Reverse Osmosis Water Filter, Alkaline Remineralization Filters for 6-Stage RO Systems, Without RO Membrane](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)
- [iSpring ICEK Ultra Safe Fridge Water Line Connection and Ice Maker Installation Kit for Reverse Osmosis RO Systems & Water Filters, 1/4", 20 feet](https://best-deals.pro/visit/ispring-ph100-alkaline-under-sink-ro-system)

## Images

![iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD — 1](https://best-deals.pro/i/fLxKdio3wGXavcpL5NcTisOzaT2-zTr0lZAUiQMyxPlkPaLFK9OtkYF675agJ_pFSA1JSvmGvd8snixOkHkXQqRmVjE0v2nb7mPfus_jShSGzAt-F-xu.jpg)

![iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD — 2](https://best-deals.pro/i/wkpe4NZHVnYFFHSOQXoOZNvyDWIAuxplwkOIBHAZBTc87S6ne8UNQul3_sTAOEsiKJ_cyotaqblAuVSz2zcG2IigDpJmkIPA6xyKpypIiZjqCiObxBF0.jpg)

![iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD — 3](https://best-deals.pro/i/ZH9LEi1SI6YnKa7NwBweTbJsoX4WCLhY-_aRN8WVudyKUTJRGXdPjmYAp6TC_XvjUL4mpLcyPZCIxNUUQWv_C-dbRmE-8KFNCeT3VGp86vy-0APULB_Y.jpg)

![iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD — 4](https://best-deals.pro/i/hP1oX_Cqq71m7gXPXVUk7RetufiWiyYUcQuZ1qQYw0ZmEkdCC8KROnxA5iKjk3o8ZQkq50saAFiP16OSloFDs4FRn1gVKDm0lPLIX9itJE-vQb6reoOf.jpg)

![iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD — 5](https://best-deals.pro/i/qowNKyLDVRfST8ZhXxlEljLlEU1zoRMpUrwtpisDl8xtGpw1hnP2k2CU6JGk0NlinN_4kglIQw2oza5cAP2ZN1c4zpkxvn0XgFgS4DoNJWXvUUtQolGp.jpg)

![iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD — 6](https://best-deals.pro/i/J6HkB2cjPm3cq3g-L8uObpv9N8xZy3sAwcrmL1HoXOiY3ZpR8TOfaEq7sY8jh2M7eAzjU9hl18zacLmyL6oROtKAl-17GYUPg8YrqSYwBg8xZvPdgooo.jpg)

![iSpring PH100 6-Stage Alkaline Under-Sink RO System, 100 GPD — 7](https://best-deals.pro/i/MWdxhAqVz-z__RCcZVCJd5UfQAJAHdn0pb693AomD1DLiH27skiw28HDc4pJMuOFUlS6Oryf4iqhGSnrZyxOaItMAbSqJ73WUFcMHmEfDE6uhU-HxhoC.jpg)