There are a number of threads discussing water filtration and storage, but I don't see anybody (ok I did see one person post) mention how to test drinking water. With a little web surfing I found a company called HM Digital that makes a pocket sized water tester that measures TDS (Total Dissolved Solids) on a scale of PPM (Parts Per Million). The device is actually measuring the electrical conductivity of the water.
I got a bunch of those from woot a couple months ago. They're not very accurate but they do measure different sources with some consistency. I think of them as better than nothing. The ones I got were just 5 bucks each or so.
As mentioned, it's better than nothing, but TDS would only tell you if there had been a gross contamination of your water and might have high readings even though your water was perfectly acceptable for drinking. Many water testers use TDS because it's a cheap and easy meter. But at our water plant, it's not even one of the things we measure for water quality because it provides no real indication of cleanliness or unsuitability for drinking.
For our reporting to the state, and this is somewhat simplified of course, there are two primary things that are measured to ensure the water is safe to drink. The first is the disinfectant residual (some form of chlorine in most water systems) which kills the vast majority of micro-organisms which can pose a health hazard. And the second is turbidity, which is basically the clarity of the water, which ensures that the micro-organisms that are encapsulated in cysts (that protect them from disinfectants) are not present. If you have a high enough disinfectant residual and low enough turbidity, your water should generally be safe to drink. There are pocket testers for these parameters just like the one for TDS, but they are more expensive.
Sorry to and most people are probably , but TDS meters are one of my pet peeves.
I've seen unscrupulous salesmen for home water purification systems use them to convince people to buy systems they can't readily afford and don't really need. TDS meters have their uses, but a go-no go test of suitability for drinking shouldn't be one of them.
Truthfully, I've never really researched them since I have access to more sophisticated testing equipment. I just recall seeing the pocket testers available in some of the catalogs. Most of our testers come from Hach.com and LabSafety.com. But I'll try to do a little research over the next couple days and see if I can find some cheap decent testers for general use. I'll post the results in this thread.
Well, I finally got a little research on this done. I was unable to find any portable testers for turbidity at a decent cost. They were all nearly $1000. But there was a decent chlorine tester at a moderate cost of $173. However, one option that I hadn't even considered (since we can't use them for compliance reporting purposes) and probably the most cost effective is the use of test strips. The accuracy of the test strips would probably be good enough for just occasional testing of your overall water quality. You can get a set of 50 tests for 5 different water quality parameters (Total chlorine, Free chlorine, Hardness, Alkalinity, pH) for just $10. Depending on the type of disinfection your supplier uses, you may have to test for either Total or Free chlorine. Due to changes in the standards for disinfection byproducts over the last several years, many water systems are switching over from Free chlorine to Total chlorine. Since you live in CA, and we all know how strict the regulations in CA are, I would lay odds that your water will use Total chlorine for disinfection.
One thing that those TDS testers are very good for is if you have a home filtration system. If you test the water going into and coming out of the filter, you can get a gross measurement of how the filter is performing. And if you keep track of the numbers, you can tell when the performance starts to degrade and it is about time to replace the filter. And if the filter ever gets overloaded, it will tend to start releasing what it filtered out earlier and you will get a higher reading coming out of the filter than the unfiltered water going in.
Thanks Don for all your research. I'm curious, does that $1k turbidity tester also test disinfectant residual too? Although it's way beyond my price range I'd like to see it if you still have the link.
Thanks again Don. I think you're right the test strips are probably the way to go for the budget minded. Still, the TDS meter I have on the way will at least give me an idea if my water filters are doing their job.