Posting in Technology
Water: how do we know what to filter or how best to filter it? We called Tom Bruursema, GM of Drinking Water Treatment Units Certification at NSF International.
Picking a new sink for my kitchen was easy. The faucet was pretty straightforward. But when it came time to select a water filter—or decide if I even wanted one—I felt paralyzed. I’ve used Britas in the fridge, Pur filters on the faucet, and my health-conscious neighbor said that her new under-sink reverse osmosis system is like the tank of water filtration systems—killing all contaminants that cross its path.
Like many consumers, I want to know what I’m drinking. And if filtration makes my D.C. water healthier (or less toxic) I’m willing to invest in a system. But how do we know what to filter or how best to filter it? When it comes to taking that next step to research what’s in our water, many of us simply buy something and hope it’s doing some good.
But now I’m on a mission to do more than hope my system is working. I’m looking for answers about what’s coming out of my faucet. So I started by calling Tom Bruursema, general manager of Drinking Water Treatment Units Certification at NSF International, a non-profit public health and safety organization that develops standards and provides third-party certification for products. Bruursema stressed that having my water tested in a lab—the step that most of us don’t take--is indeed the best way to learn about the contaminants. I’ll attempt to tackle that next. Excerpts of our conversation are below.
I’m guessing I’m not the only one who is confused about water filters.
It’s confusing, but it’s a popular product. There’s a lot in the news continuously about water quality. It leads to consumers having a strong interest in the category and wanting to manage water quality in the home. It’s not an insignificant purchase. and if done properly would improve the chances of consumers really achieving what they want.
How accurate are home testing kits at detecting contaminants?
For the ranges that they cite on the packaging they are probably reasonable. The disconnect is that those levels are not the levels you’d need to know to determine whether there is an actual health concern. So their detection quality will not reach the level that a consumer would want.
Lead would be an example. You can’t taste it, you can’t smell it, so the typical type of equipment a laboratory would use is far more sensitive [than a home testing kit]. That’s for a health claim; there are other chemicals that are detectible by taste and odor like chlorine or the hardness of the water. So certain things may well be suitable for testing those but not for the health concerns.
So how do you recommend testing?
You’d want to use a certified laboratory, and there are many available in every state. They’ll often provide you with a sample bottle to send in the water. You’ll find that some local health departments will do it for free. Private labs can range from $15 to $20 and up.
So assuming you can trust your city’s water testing, why would you also need to test your home water?
The difference would be that with the water coming from your specific tap, there may be plumbing components that aren’t fully represented. But the city’s report is a great source of information.
Do you think people tend to trust bottled water more, even though we don’t necessarily know what’s in there?
I think they’d tend to probably trust it more. There are certainly requirements for bottled water as there are for public water supplies. We’d encourage consumers to make sure bottled water is meeting certain FDA requirements and has third party certifications.
Some people think that if your water has an off-taste or an off-smell that implies that it’s unsafe. That’s a big misconception. Some are deliberately there—like the chlorine. But generally people associate an undesirable effect as far as taste and odor with health concerns.
But on the flip side, it could have no off-taste and no off-smell but have contaminants. So if people are concerned about the health of their water it’s important they get it tested.
Is there a risk of filtering out some good things if you filter too much?
There is the potential that you could reduce things that are not of concern. For most people we have enough sources of things such as calcium and magnesium in our daily diets.
How much do we know about the long-term health effects of the most common contaminants?
We definitely know a lot about the regulated compounds—the things that are required to be monitored. The Safe Drinking Water Act addresses the primary water regulations. Lead, mercury, arsenic are some of the metals and then there are some pesticide sand herbicides. It’s quite a long list.
I’ve been hearing more about reverse osmosis filtration and that it filters out the most contaminants. Can you explain how it works?
It incorporates several different technologies. Most systems will include a sediment filtration and a carbon filtration. But what’s different is that it uses a membrane which rejects unwanted contaminants while allowing the water to go through. It’s like a water sieve. It does remove and reduce quite a wide range of contaminants. It tends to be a larger system, so often they're installed under a sink. The water production would be slower than some other technologies, but they balance that by having a tank so there’s a reservoir available.
When we talk to consumers about this category, we encourage them to look at what technology meets their particular needs—size, maintenance, how many of the cartridges need to be replaced, what it removes. They need to ask, what do I really need in terms of contaminant reduction. Reverse osmosis does a lot of things, but you may not need something that does a lot of things. On the other hand, if you have arsenic, you might very well want to look at reverse osmosis, which is the primary filtration to treat for arsenic.
It is. The portions that are unwanted go down the drain. Because of the membrane, there is a certain amount of water that is used in that cleansing process. The ratios differ by technology. There are some efficiencies to improve upon that. But all those systems will waste some water.
So it sounds like for some home’s needs, reverse osmosis would be overkill.
Consumers should look at their options and see what they need for their specific water. There are refrigerator filters, carafe style filters and faucet attach filters.
But these are products you don’t really know if they’re doing what they say they’re doing. Most products in the marketplace do carry a third party certification. So that’s the final step after you decide which type and style, before you purchase. The NSF mark is a very obvious and very prominent one. We certify about 5,000 product models. This is a large category with a lot of products.
Are there any new technologies or systems on the horizon?
Not that are dramatic reinventions of the marketplace. There certainly are new technologies that are coming into the marketplace that continue to enhance and move the industry forward. Some are alert systems—when to change the cartridge, when things should be maintained.
The certification looks at a whole range of things such as alert devices and material safety to make sure the materials themselves don’t produce contaminants.
Does anyone change their filters as often as the products recommend?
We understand and expect these will not be changed at the frequency they should be. For those who don't have any kind of an indicator, our standard requires we test to twice the claimed life of the product. So if it says it’s effective for 600 gallons [for health reasons] we’ll test for 1,200 gallons. But that’s not license to change half as often.
Jun 14, 2011
"Picking a new sink for my kitchen was easy. The faucet was pretty straightforward. But when it came time to select a water filter???or decide if I even wanted one???I felt paralyzed." Yeah right, this is my problem. I am currently looking for a great water filter for my kitchen,i found this water filter (http://waterfilters.mercola.com/drinking-water-filter.aspx) and i don't have any idea about it, any idea about this?
Good Article on home water filtration. Do the Water Filters which neither use UV or heating kill Microorganisms? Thermal or UV and both are needed to kill the microorganisms. Microorganisms are heat sensitive. Temperatures required to eliminate microorganisms within 60 minutes: Salmonelle 58 Degrees Celsius Shigella 54 Degrees Celsius Vibrio Cholera 45 Degrees Celsius Entamoeba Histolytica Cysts 50 Degrees Celsius Giardia Cysts 59 Degrees Celsius Hookworm Eggs and Larvae 51 Degrees Celsius Ascaris Eggs 57 Degrees Celsius Schistosomas 50 Degrees Celsius Taenia Eggs 51 Degrees Celsius (Source: SODIS Technical Note# 9,published by EAWAG and SANDEC). In our Solar Disinfection Unit even in 30 Degrees Celsius Ambient Temperature(February) in South India we are getting around 60 degrees Celsius water temperatures inside bottles. It can be seen that it is not required to boil the water in order to kill 99.9% of the microorganisms. Heating up water to 50-60 Degrees Celsius for one hour has the same effect. Our system(6 litres) capacity costs just Rs 1200(About US 25) in South India and it can be manufactured locally Community systems of 50 or 100 litres capacity can be fabricated. What all it requires is exposure to sunlight for 5 to 6 hours(with ambient temperatures around 25 degrees Celsius.. Our Solar Disinfection system is expected to be a boon for developing countries. Dr.A.Jagadeesh Nellore(AP),India E-mail: email@example.com
Whatever it takes to produce water of known water quality is not "waste"...Many parts of the country have mysterious "cancer clusters" that the bureaucrats overlook...In my mind at least, drinking water quality is a logical suspect. My recommendation for drinking water is to run RO water through a Zerowater Pitcher, and you will end up with demonstrably purified water to drink.
I bought my counter top distiller in 1982 when I first learned i was expecting a baby. I have turned it on every single night since July of 1982 to have 4 gallons of fresh distilled water by morning to cook/drink. The workhorse of a machine is American made, all stainless parts and has never failed -- not once. The water has been tested by a certified 3rd party and it is incredibly clean and sweet tasting. And while it does use energy...it doesn't waste water. I recommend distillation and wonder why this consideration was not included in your review. jtk
If you're on a municipal water supply, they are required by law to test for contaminants using independently certified labs, and annually report that infomation to you the consumer. If there is a significant violation, they have to report that at the time of violation. So unless there's an identified problem (which they will have to fix anyway), you could find yourself spending a lot of money on additonal water treatment for peace of mind with no real result. If you're on a well, it won't hurt to have your water tested, but unless you have a reason to suspect contamination, you're most likely fine there too. Personally, I maintain the carbon filter on our home refrig icemaker/water dispenser and keep a Brita filter at work. Not for health concerns, but simply because I think chlorine, particularly chloroamines, taste like crap. For just about everyone reading this, there's only a couple of reasons for spending your hard earned money on point of use devices. That would be for either taste, or for non-health related issues such as high levels of hardness, or things such as high iron or sulfur levels. Written by someone with 35 years experience in water treatment.
I have used an American made distiller for the last year and it is a great option. I was purchasing gallon bottles of distilled water as well as cases of bottled water for home use, so I bought it partially for a financial reason (it's now paid for itself) as well as having total control over the process to assure their has been no tampering with the water my family drinks.
The problem with your average "open" distillers is that whatever "volatile organic compounds" (jet fuel?) (just kidding...) that are present in the feedwater will be released into your ambient air...so you have to guard against that...
I completely agree. In addition, there are much tighter standards for tap water than bottled water (for which regulation is very young yet). As for RO units, the wash and waste also has a very negative effect on your waste treatment plant as it concentrates minerals and wastes that a waste treatment plant is NOT designed to remove and ends up dumping more contamination into the waterway the plant discharges to. There's no free lunch as they say. Hysteria in the news media is the main marketer of most devices in my opinion. Simply look at the required annual Consumer Confidence Report (CCR) for your water system. (7 years public health chemist/microbiologist, 33 years municipal water treatment and QC laboratory).
The amount of water a typical home drinks and thus sends through a filtration system is a tiny percentage of overall use. How much water does a typical person use for drinking and cooking each day? I'd be surprised if it's even five gallons. When compared to the water used for toilets, bathing, and washing clothes, it's a tiny percentage (outside water used for watering -- the bulk of most home use -- mostly stays in the ground though there's still runoff that winds up at the water treatment plant). And RO doesn't add any pollutants that weren't there already. The water a RO filtration system sends down the sewage line is a little more concentrated than before filtration, but it gets diluted at the water treatment plant. The alternative is that people consume unfiltered water with all the trace contaminants. Either they absorb contaminants (e.g., lead) or they excrete them and they get passed to the water treatment plant anyway. I guess I'm selfish, but I do care about this stuff getting into my body especially when it will be in the general water supply anyway if I don't treat what I drink. It comes down to either using a RO system to filter contaminants, or essentially using your body. The big question whether or not all the trace contaminants such as lead, arsenic, urine salts, soaps and detergents, excreted human medications, fertilizers and pesticides accumulated from farmland runoff, etc. are a factor. Clearly they're not on a day-to-day basis, but the unknown question is how much they affect us over a lifetime. The final evidence is not in about the long term effects of trace contaminants, but I don't think anybody should feel guilty about the affects on the general water supply of installing a RO system.
...And if you want to spend it that way, more power to you. But just realize whatever incremental health risk reduction you've realized by purchasing and installing that unit, you probably negated it the next time you exceeded the speed limit, crossed a street midblock, or any of a hundred other ways you place yourself at risk on a daily basis.