lakeside7 Posted January 25, 2014 Report Share Posted January 25, 2014 Following news item, I wonder if it will happen in Lakeside ""It's a suggestion alien to Mexico City residents who have long shunned tap water in favor of the bottled kind and to the throngs of tourists who visit the city each year, bringing with them fears of "Montezuma's Revenge." But a law recently approved by Mexico City's legislators will require all restaurants to install filters so they can offer patrons free, drinkable water that won't lead to stomach problems and other ailments."" Link to comment Share on other sites More sharing options...
ComputerGuy Posted January 25, 2014 Report Share Posted January 25, 2014 Hmmm, Mexico City's or the Federal legislature? In any case, the only laws that ever arrive quickly are the ones with higher tax rates. Link to comment Share on other sites More sharing options...
Yo1 Posted January 25, 2014 Report Share Posted January 25, 2014 I would still drink bottled water if I wasn't the one in charge of maintaining the filter. Link to comment Share on other sites More sharing options...
Alpha1 Posted January 26, 2014 Report Share Posted January 26, 2014 I would carry a HM Digital TDS-4TM Meter to check the filtering.... Link to comment Share on other sites More sharing options...
mudgirl Posted January 28, 2014 Report Share Posted January 28, 2014 If restaurants will not give their patrons a glass of garafon water because it costs 15 pesos/garafon, which amounts to a small fraction of a centavo/glass, that has to be the cheapest attitude I have ever heard of. I would imagine installing the new filters and changing the cartridges regularly will be far more expensive. And who is going to check to see that the cartriges are replaced when needed? Link to comment Share on other sites More sharing options...
maryannborman Posted January 28, 2014 Report Share Posted January 28, 2014 FYI, Just a reminder if you are using your digial device todetermine water purity. The digital device only detects heavy metals and other particiales from the water. It does not detect bacteria or other waterborne biological contaminents. These can only be determined by lab testing. Link to comment Share on other sites More sharing options...
snowyco Posted January 28, 2014 Report Share Posted January 28, 2014 I would carry a HM Digital TDS-4TM Meter to check the filtering.... A TDS*** meter measures conductivity, which usually comes from dissolved salts - which by definition cannot be filtered - so the digital meter listed here does not check filtering. Heavy metals like lead, cadmium, and nickel at toxic levels are not really measurable by a TDS meter. A TDS meter gives much higher readings for mineral water, due to the harmless dissolved salts, than tap water. Do we think mineral water is contaminated? TDS meters are good at measuring salinity, but they do nothing for measuring pesticides, organic solvents, oil products, nor bacteria nor heavy metals contaminants. ***TDS = Total Dissolved Solids - things that pass through a filter. This means that TDS measurements are the same for before-filtering and after-filtering. The amount of dissolved salt stays the same whether filtered or not. Link to comment Share on other sites More sharing options...
RVGRINGO Posted January 28, 2014 Report Share Posted January 28, 2014 Thanks for explaining that. I was tempted, but thought that the gullible ones might form a posse. Some folks will believe anything and I am amazed at how few understand basic science. The current fad for Natural Products reminds me that BS is natural, and so is ours: many will live with leaking septic systems, while complaining of dog droppings on the sidewalk. The former is dangerous, tha latter, hardly at all; even if slippery. Link to comment Share on other sites More sharing options...
Mainecoons Posted January 29, 2014 Report Share Posted January 29, 2014 I suspect that the greater problem with Mexican water supplies is not in the source, it is in the erratic distribution and poor construction of pipelines. When a system is depressurized, as often happens here, it opens the door for polluted water to infiltrate from outside of the pipe. At least in our location, the reliability and quality of water delivery has really improved. We treat our own drinking water and have had absolutely no problem for nearly 6 years. However, I'm a maintenance fanatic and water engineer so I have our treatment system in top operating condition and watched like a hawk. Link to comment Share on other sites More sharing options...
Alpha1 Posted January 30, 2014 Report Share Posted January 30, 2014 A TDS*** meter measures conductivity, which usually comes from dissolved salts - which by definition cannot be filtered - so the digital meter listed here does not check filtering. Heavy metals like lead, cadmium, and nickel at toxic levels are not really measurable by a TDS meter. A TDS meter gives much higher readings for mineral water, due to the harmless dissolved salts, than tap water. Do we think mineral water is contaminated? TDS meters are good at measuring salinity, but they do nothing for measuring pesticides, organic solvents, oil products, nor bacteria nor heavy metals contaminants. ***TDS = Total Dissolved Solids - things that pass through a filter. This means that TDS measurements are the same for before-filtering and after-filtering. The amount of dissolved salt stays the same whether filtered or not. Absolutely right...however if the TDS reading was low then it MAY indicate that the water was filtered....not an indication of purity but a possibility that it had been filtered... Link to comment Share on other sites More sharing options...
snowyco Posted January 30, 2014 Report Share Posted January 30, 2014 I'm confused. Since filtering does not change TDS, and TDS meter readings are the same for both filtered and unfiltered water, how can a TDS meter tell you whether tap water at your table has been filtered? Maybe it is a matter of semantics? Many water purification techniques are not filtering: Electropurification is not filtering. Ozonation or UV light treatments are not filtering. Reverse Osmosis (RO) is not filtering. Did you mean purification? RO reduces TDS readings but ozonation and UV treatments can actually increase TDS readings. This means that TDS meter readings are not a reliable for measuring if water is purified or safe to drink. Clean (safe to drink) ozonated water can have TDS readings, while low TDS drinking waters can often have bacteria - like ice tubs in McDonalds or Burger King drink dispensers. This is really common because the ice tubs in the Coke and Pepsi machines are not frequently disinfected. Same thing goes for iced tea and glasses at restaurants, which is why a lot of Mexicans use straws, to not touch their lips to the rim of the glass. Water with higher TDS readings can be very safe to drink - like mineral water, while low TDS waters may or may not be safe to drink. TDS readings = lots of false negative measurements of water safety. Link to comment Share on other sites More sharing options...
TioBob Posted February 1, 2014 Report Share Posted February 1, 2014 My understanding is TDS meters were developed to determine when it is time to change RO membranes. You are correct, they don't measure bacteria. If you get a high TDS reading from RO processed water you should be concerned the membrane did not remove contaminants that are normally removed through the RO process. It is time to change the membrane. Link to comment Share on other sites More sharing options...
Alpha1 Posted February 2, 2014 Report Share Posted February 2, 2014 I'm confused. Since filtering does not change TDS, and TDS meter readings are the same for both filtered and unfiltered water, how can a TDS meter tell you whether tap water at your table has been filtered? Maybe it is a matter of semantics? Many water purification techniques are not filtering: Electropurification is not filtering. Ozonation or UV light treatments are not filtering. Reverse Osmosis (RO) is not filtering. Did you mean purification? RO reduces TDS readings but ozonation and UV treatments can actually increase TDS readings. This means that TDS meter readings are not a reliable for measuring if water is purified or safe to drink. Clean (safe to drink) ozonated water can have TDS readings, while low TDS drinking waters can often have bacteria - like ice tubs in McDonalds or Burger King drink dispensers. This is really common because the ice tubs in the Coke and Pepsi machines are not frequently disinfected. Same thing goes for iced tea and glasses at restaurants, which is why a lot of Mexicans use straws, to not touch their lips to the rim of the glass. Water with higher TDS readings can be very safe to drink - like mineral water, while low TDS waters may or may not be safe to drink. TDS readings = lots of false negative measurements of water safety. Everything you state is true. If the water did go through an RO system then the TDS readings should be lower than simple tap water. As I stated it is not definitive only an assumption... The TDS reference was to be taken tongue in cheek... Link to comment Share on other sites More sharing options...
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