If you are looking for a water filter that is a bit more permanent than the pitcher products, look no further than the iSpring RCC7. This under the sink water filter delivered an exceptional performance in our lead removal and chlorine removal tests, leaving only trace amounts of the contaminants behind.This filter also gave a great showing when we evaluated its ability to extract minerals from your water supply and delivers great tasting water, failing to impart any negative tastes on clean water and removing bad tasting compounds. It doesn't have the highest flow rate and is a little on the pricey side, but it is the best bet for those that don't want to have to constantly be refilling a filter pitcher and are looking for a more permanent fixture in their kitchen.
iSpring RCC7 Review
Pros: Great at removing both lead and chlorine, makes great tasting water
Cons: Mediocre flow rate, pricey
Compare to Similar Products
Our Analysis and Test Results
The iSpring tied with the Home Master HydroPerfection for the overall runner-up position, right behind the ZeroWater 10-Cup Pitcher. This pair of filters both did a superb job at removing chlorine and lead, but the iSpring has a slight edge when it came to removing minerals from the water, though the HydroPerfection does have a superior flow rate. However, the iSpring costs about half of what the HydroPerfection does, making the iSpring the clear winner.
To see which water filter is really worthy of an award, we bought all the best and pitted them against each other in a brutal series of head-to-head challenges. We divided up the various tests among five weighted rating metrics — Lead Removal, Chlorine Removal, Taste, Mineral Removal, and Flow — with the following sections describing how the iSpring did and how it compared against the rest of the competition.
One of our most important metrics, our Lead Removal metric comprised 25% of the total score for each filter. To judge this, we spiked our isolated water supply to exceptionally high concentrations of lead, then ran it through each filter. We did this by dissolving lead flakes into a mixture of hydrogen peroxide and vinegar, then added this solution to our water supply. The iSpring removed practically all of the lead, earning it top marks.
After running all of the contaminated water through the filters, we sent our samples off to an independent water quality lab to measure our results. Our supply water reached a lead concentration of 2.3 ppm — over a hundred and fifty times higher than the acceptable level in drinking water, as stated by the EPA. The iSpring reduced the concentration of lead to about 15 times less than the EPA's limit, extracting about 99.96% of the lead in the water supply.
For the next metric, we moved on to looking at how well each water filter did at removing chlorine from your tap water. These tests account for 25% of the total score, with the iSpring again delivering one of the best performances that we have seen.
We used chlorine bleach to taint our isolated supply, then used both test strips and an electronic meter to measure the concentration of our water samples. We did two tests for this metric, one with extremely high levels of chlorine and one with a more moderate concentration. The concentration was over 1300 ppm in the high concentration test and around 50 ppm in the moderate concentration test. The iSpring did very well in both of these, reducing the concentration low enough to where the test strips wouldn't even register any chlorine — very close to completely removing all of the chlorine.
Similar to the prior two impurity removal metrics, this one also is responsible for a quarter of the overall score for each water filter. For our sample mineral, we used standard table salt and again used our electronic Total Dissolved Solids (TDS) meter to measure the concentrations and score the performance of each filter. The iSpring again did exceptionally well, though it couldn't quite nab the top spot this time.
This filter successfully reduced the concentration of salt from about 445 ppm to around 20 ppm — a reduction of over 95%. However, it couldn't quite match the ZeroWater Pitcher, which completely removed all of the salt from the water.
Our next metric, accountable for 15% of the total score for each product, judged how crisp and clean each filter made the water taste. We conducted two different tests, one with purified water and one with foul-tasting water with very high levels of chlorine and salt, to see if the filter added any undesirable flavors to clean water and to see if it could remove these flavors. The iSpring again scored exceptionally well, though it again fell slightly short of the top spot.
This filter passed the first test with flying colors, with our panel agreeing that the purified water passed through the iSpring was indistinguishable from the bottle. This filter also removed the vast majority of the unsavory flavors from the contaminated water, but most of our tasting panel could detect some residual chlorine and salt tastes.
For the last metric of our test, responsible for the residual 10% of the total score, we analyzed and scored the flow rate of each filter. The iSpring delivered a rather unimpressive performance, putting it right in the middle of the group.
We evaluated the performance of each filter by how long it took to fill up a quart container, including the time to refill and filter more water if necessary. The iSpring took about 33 seconds — roughly three times longer than the standard faucet.
While this is an excellent filter, it's not the best bet if you are shopping on a budget. There are other under the sink filters that are less expensive with only a slight drop in performance and pitcher style filters are far superior when it comes to shopping on a tight budget.
The iSpring RCC7 is an excellent product overall and is our favorite of the permanent install filters. It does an amazing job of extracting lead, chlorine, and minerals from your water, producing crisp and refreshing tap water. If you want the best of the best and don't want to fuss with refilling a pitcher, then the iSpring is the filter for you.
— David Wise and Austin Palmer