Drip Drop Water Talk

Separating the sales pitch from science

Factors that Contribute to Drinking Water Quality

factors affecting water quality


Q: What factors contribute to the quality of a city’s drinking water?  It appears according to a recent report, 10 U.S. cities with the worst drinking water, that Florida has two cities which show up on the list (Jacksonville and Pensacola). For a peninsula, you would think the quality would be better. How does the natural Floridan aquifer affect the quality of the water (other than providing a sandy taste)?


A: The two biggest factors that contribute to the quality of a city’s drinking water are 1) the source of the water and 2) what treatment methods are employed before sending the water out.

Jacksonville has a lot of disinfection by-products in the water.  It’s hot there and biological contaminants will grow pretty easily in the water so the city uses disinfectants such as chlorine to reduce the growth of microorganisms.  The chlorine will react with organic matter that is present in nearly all water systems to produce disinfection by products.  According to Jacksonville’s website their water comes from a limestone aquifer so the source of water isn’t bad, they just use chlorine to keep biological contaminants out.

Pensacola has the deck stacked against them with their source water.  There the water comes from 32 sand and gravel aquifers, which many organic contaminants can easily leach through to get into the water table.  The water utility tries to clean up the water with a lot of adsorption media but it’s expensive to treat a lot of water that’s going to be used in toilets and for watering your lawn.


Find this question and others I’ve answered on Quora.  

All About Lead: Keeping your water safe

All About Lead is part of a series.  To be updated on when the next installment please subscribe to my mailing list.

The ability to have clean drinking water is something most residents in the United States take for granted.  When you’re in a situation where your water isn’t clean, it’s colored, smells weird, whatever, you feel helpless.

This isn’t supposed to happen.  This is America!  Not India.  Not Haiti.  We’re supposed to have clean water.  

It’s hard to see contaminants in water with our eyes; things like lead and cryptosporidium aren’t visible to the naked eye.  

With the on-going crisis in Flint, Michigan, lead is a hot topic these days.  There is a lot of information out there about the problem, but very little information about the actions people who are living with lead water can take to protect themselves.

In this three-part series I’m going to address the history of lead in plumbing distribution, the science behind why Flint is now full of lead, and what actions people can take to remove lead from their water.  

Let’s get started.


The History of Lead in Plumbing

The History of Lead in Plumbing

Most of us know that lead is bad so it’s hard to fathom the possibility of there being lead in the water.  In fact, lead is one of the best studied toxic-substances and we know more about the negative health effects than almost any other chemical.  This abundance of information however is unfortunately due to lead’s predominate use throughout history starting in the Roman Empire and extending through the 1990s.  

In Plumbo Nos

The Roman Empire is credited with being the first regime to mass-distribute lead due to their massive mining operations.  Lead itself does not occur in an elemental state but is a by-product of silver and gold mining.  It is readily available, easy malleable, is resistant to corrosion, and is easy to melt at low temperatures making it an ideal material for creating products out of.  

The Romans used lead extensively.  The used it to create plates and silverware, cooking utensils, urns for wine, makeup, and indoor plumbing.  In fact, the word plumbing itself is derived from Latin.


That’s Latin for lead.  


Fond of bathing, the Romans constructed great aqueducts to transport water from miles away to baths and recreation centers.  They were the original plumbers, lead workers who were responsible for measuring and laying out pipe, soldering, installing, and repairing the infrastructure that moved water around cities such as Rome and Pompeii.  

It should be noted that not all plumbing was created out of lead, some were created using terra cotta pipes.

With the decline in the Roman Empire so came the decline in plumbing.  Bath houses came to be viewed as places of debauchery and cleanliness decreased in value.  

It wasn’t until the mid-1800s when diseases like typhoid and Cholera were rampant that the link between bacteria and disease was discovered by Louis Pasteur.  Plumbing, especially to keep clean water isolated from wastewater, became of increasing importance. 

The New World and Lead

Almost as soon as the first colonists settled in the United States the mining and smelting of lead began.  Lead was originally sought out for its use in ammunition and by 1621 the metal was being mined and forged in Virginia but it wouldn’t be until later that lead would be used to transport water.

Early water distribution systems were created using bored-out logs, usually from hemlock or elm trees.  In 1652 Boston unveiled the country’s first water distribution system using these hollowed out trees in order to provide water for firefighting and domestic use.  

There were several problems with using wooden pipes however.  Uneven ground would cause the pipes to sag, creating pockets of stagnant water that developed a woody taste over time.  As cities expanded more pressure was needed to move the water farther and farther and this would cause the wooden pipes to split.  

As wooden pipes ceased to be useful, a switch to iron was made.  The city of Philadelphia became a global leader in plumbing when it became the first city to distribute water using entirely cast iron pipes in 1804.  Other cities such as Chicago, New York, and Boston followed suit.  

As plumbing knowledge evolved, so did the ease of bringing water inside homes.  Instead of getting water from a pump in the street one could get water from a faucet inside your house.

 Designing piping to move water around cities was fairly easy and straightforward but when it came to connecting buildings to water mains things became more complex.  There were a lot of pipes and conduits in the streets so piping that was flexible was highly desirable.  

The connections from water mains to buildings are known as service lines and creating these pipes out of lead became the most practical solution for engineers.

Lead service line location

Lead in the 20th Century

By 1900, of the 50 largest cities in the United States all but six or seven of them has installed lead piping.  New York, Chicago, Philadelphia, Saint Louis and Boston all used lead services to varying degrees.  

Many local building codes mandated that lead service pipes be used for constructing service lines.  Lead is more durable to corrosion than iron piping and many of the lead pipes that were being used in 1900 are still in use today.  

A committee on service pipes submitted a preliminary report to Engineering News, a journal of civil engineering and construction that was issued weekly, on the use of lead service pipes in 1916.  The report stated:

Lead is in many respects the most satisfactory material to use for service pipes. Its pliability and its comparative freedom from corrosive action make it almost ideal from a mechanical standpoint. The cost of lead pipe of sufficient thickness safely to withstand the pressure is more than the cost of many other materials used for service, but in a paved street the greater duration of life probably more than compensates for the extra cost, and in places where the streets are occupied by other pipes and conduits the ease of getting over and under these obstructions with a flexible pipe is a great advantage.

The article continues:

The most serious objection to the use of lead pipe for services is the possibility that the water may dissolve enough lead from the pipe to cause lead poisoning. It is certain that many cases of lead poisoning have been caused by the use of lead services.  On the other hand, lead has always been used for services in most of the large places without any unfavorable effects.

Engineers knew lead pipes were bad and could poison people but didn’t understand why in some areas people became poisoned and in others people were fine.

It seems to be practically impossible to determine definitely in advance what the effect of any water on lead pipe will be, as the laboratory results fail in many cases to show the action which will occur in actual practice.  Tests of service pipes in use for a considerable period are the only safe guides.

This highlights a key point in the use of lead pipes.  

Not all lead pipes pose a health risk.  

Not all lead pipes pose a health risk.

If the water chemistry is good, with a pH that’s close to neutral and not overly corrosive water, then lead pipes can be perfectly safe.  

In the 1930s copper pipes or galvanized steel pipes began to replace most of the lead pipes in residential plumbing.  Solder, a material that’s used to join together metals like copper pipe, still contained lead until it was banned for plumbing applications in the 1980s.  

The importance of lead dissolved from lead service lines has received little attention until now because over time oxidation created a protective coating along the interior of the lead pipes.  This limited the amount of lead that would leach into the drinking water and could be ingested.  

This brings us to today, where residents in Flint, Michigan, have been struggling with lead contaminated water since the summer of 2014.  

In a couple weeks I’ll be sharing the science behind how Flint became full of lead.  To be one of the first to know when the next installment is available please subscribe to my mailing list. 

World Water Day


Today is World Water Day.  A day of international observance, an opportunity to learn about water related issues, a day to be inspired and tell others about water, and a day to take action to make a difference.

March 22, 2016 marks the 23rd annual celebration of water.

Most of us are lucky to be able to turn on a faucet and have as much clean water as we’d like come out.  Unfortunately, there are many around the globe – and even in the US, who lack access to clean water.

Each year United Nations-Water, the entity that coordinates the UN’s work on water and sanitation, sets a theme for World Water Day corresponding to a current or future challenge.  This year the focus is “water and jobs” and for the first time the report will be released in Spanish and French, in addition to English.  Read more about the launch of the report here: www.unesco.org.

This year is also the first year that the United States White House will be hosting a Water Summit with live streaming of the event here: www.whitehouse.gov.

Today I’d like to challenge you to try these simple ways to conserve water:

  • Turn off the faucet while you brush your teeth.  This can save up to 8 gallons of water, up to 200 gallons of water per month!
  • Take a shower instead of a bath.  A shower typically uses 10 to 25 gallons of water whereas a bath will consume up to 70.
  • Check that your toilet doesn’t leak.  Leaky toilets end up wasting 200 gallons of water per day.  Check for a leak by putting food coloring into the tank and see if it ends up in the bowl without flushing.
  • Water your plants in the early morning or late evening.  If you water your plants and lawn when it’s hot and sunny the water can evaporate before the plants have a chance to drink it.

How will you make a difference today?

Reverse Osmosis and Bacteria

Do reverse osmosis filters remove bacteria-

Q: Do reverse osmosis filters remove bacteria?  How?

A: Yes, bacteria will be removed via reverse osmosis due to size exclusion (i.e. the bacteria are larger than the pores in the reverse osmosis membrane so they can’t pass through).  However there can be defects in the membranes which allow the bacteria to pass through.  I’ve also seen it hypothesized that the bacteria will move around the o-ring which typically seals the reverse osmosis into place within its housing.  Secondary contamination, where bacteria will move up the pure water stream and attach to the membrane, is also a possibility.  This is why while bacteria can be removed via reverse osmosis, these systems are rarely certified to be microbiological purifiers.


Find this question and others I’ve answered on Quora.  

The Impact of Holiday Spices on Water

Holiday Spices

The Puget Sound is a large ocean inlet along the northwest coast of the state of Washington on the Pacific Ocean.  Seattle is located on the sound and enjoys being the eighth largest port in the United States.  If you were to visit Seattle today you’d likely visit the Pike Place Market and enjoy the fish vendors tossing fish around, or walk along Pier 66 taking in the view of the city at night.  The water within the sound is a meaningful piece of Seattle and keeping the water clean is important to the prosperity of the city.

Scientists at the Center for Urban Waters within the University of Washington Tacoma are working to understand and quantify the sources, pathways, and impacts of chemical pollution in urban water systems.  One program at the center, called Sound Citizen, studies pollution involving fun compounds, such as cooking spices, and more serious pollution, such as emerging pollutants.  The pollution of cooking spices in water systems is an interesting research area as it’s not an area of pollution that most people think about.  Just like pharmaceuticals that end up in water after passing through the human body, many spices end up in local water systems the same way.  This project focused specifically on spices, acting as a way to help people see the connections between humans and natural environments.

Tracking the presence of cooking spices in the Pudget Sound allows researchers to track the holidays.  In the summer the water contains high amounts of methyl-vanilla, an ingredient found in waffles cones and kettle corn.  After Thanksgiving and Christmas the water is full of vanilla and thyme, entering the sound through the water treatment plants.  At the West Point wastewater treatment plant in Seattle researchers have measured an increase in spices such as cinnamon, vanilla, allspice, thyme and rosemary starting immediately after Thanksgiving and lasting through the New Year. Converting the amount of spices detected in the Puget Sound into the amount of baking spices needed to make chocolate chip, gingerbread and snickerdoodle cookies, researchers determined that about 250,000 cookies were being consumed each day during the 2008 holiday season.  At that time the average person in Seattle was eating two cookies per day!  The population of Seattle has increased by over 50,000 people since 2008 and the amount of spices in the Sound has also likely increased.

At this time the effects of an increase in spices on fish and wildlife have not been explored.  Salmon fish use open-water navigation and a keen sense of smell to find their way back to the very same stream in which they were born.  The spices being detected in the Sound are at levels that fish can easily smell.  Until more research is completed however, the effects of “pumpkin spice everything” on fish and wildlife remain unknown.

(Photo credit: Happy Holidays 2016)

Treating for Pharmaceuticals and Personal Care Products


The detection of new contaminants such as pharmaceuticals and personal care products in drinking water has opened up a new opportunity in the water treatment world to innovate and design new technologies that can address these contaminants.  In order to address concerns about the performance and claims used by marketers for treating water in a household, the National Sanitation Foundation (NSF) created a series of American National Standards (ANSI) to confirm the claims are true, the system doesn’t impart anything harmful into the water, and that the product labeling isn’t misleading.

A new standard NSF/ANSI 401: Emerging Contaminants/Incidental Compounds has been developed to verify the ability of a drinking water treatment device to reduce 15 emerging contaminants such as DEET, Ibuprofen, Estrone, and Bisphenol A.  Most contaminants certified by the NSF are either classified as “health effects”, which are contaminants known to adversely affect health when present in water, or as “aesthetic effects”, which are contaminants known to adversely affect the taste, odor, or appearance of water.  Emerging contaminants however are a new category created to address the concerns over contaminants whose health effects have not yet been established.  The contaminants used to challenge water treatment devices under the new standard include prescription/over-the-counter drugs, herbicides and pesticides, and chemicals used as flame retardants and detergents.

At the time of this post (12/1/2015), 22 manufacturers have certified 156 different products to this standard.  The products which have been certified include point-of-entry (POE) and point-of-use (POU) devices such as refrigerator filters, counter top units, faucet mount filters, and under sink units,  The list of products which are currently NSF 401 certified can be found on NSF’s product and service listing’s page.

New Membrane Material Developed which may Compete with Current Desalination Membranes

MoS2 membrane

Move over graphene, there is a new membrane material in town!

Researchers at the University of Illinois at Urbana-Champaign have developed a new membrane material for water treatment.  This material is a nanometer-thick sheet of molybdenum disulfide (MoS2) which is riddled with tiny holes ranging from 1 to 10 nm in diameter called nanopores.  Today the market is full of reverse osmosis (RO) membranes which typically have a pore size of 0.1 nm but are thick due to their polymeric material.  This thickness has a direct relationship on the amount of energy it takes to push water through the membrane and current advances to increase the recovery rate of water through an RO membrane are limited to the orientation of membrane leaves (individual sheets of membrane through which water passes).  By creating a thinner membrane, less energy is required to filter water and lower operating costs are feasible.  Despite its thinness MoS2 is mechanically robust with an effective Young’s modulus of 270±100 GPa (about that of steel), which is not completely surprising considering that molybdenum is frequently used for making high strength steel alloys and superalloys.

In order to determine the effectiveness of the MoS2 membrane for water permeation, it was compared against conventional water treatment membranes: MFI-type zeolite, seawater RO, brackish water RO, nanofiltration, high-flux RO, and including graphene.  The permeation rate was found to be two to five orders of magnitude higher than conventional membranes and 70% greater than graphene.  This increased transport of water was attributed to the architecture of the pores within the membrane.  Molybdenum is located in the center of the membrane which attracts water, and the sulfur on the other side which pushes the water away.  Ion rejection rates of the MoS2 membrane were on par with that of seawater RO membranes and graphene.  Further testing is expected to look at fouling of the MoS2 membrane.

Friday Five, 2015-08-28


1) People in California were able to cut their water usage by 31% as compared to July 2013.

2) Hours before the new Environmental Protection Agency ruling “waters of the United States” was due to go into effect, a federal district court in North Dakota blocked implementation.

3) This is ridiculous.  Russell Wilson, quarterback of the Seattle Seahawks, claims that drinking Recovery Water healed a head injury.  No.

4) The city of Toledo, Ohio, is on alert due to an algae bloom on Lake Erie.

5) Stonehouse Water Technologies has placed a small drinking water filtration system along the Menomonee Canal in Milwaukee, Wisconsin, which people can use to obtain clean drinking water.

(Photo credit: Kristen Brastad)

The Drinkable Book

Problems with drinking water and sanitation in many developing countries go hand in hand.  Earlier this year Unicef and the World Health Organization published a report lauding the accomplishments made to deliver safe drinking water to people, an effort which has been undermined by a failure to meet global targets for improved sanitation.

To help combat this the organization WaterisLife is working in conjunction with Dr. Theresa Dankovich to develop The Drinkable Book, an instructional manual for how and why to clean drinking water as well as acting as a water filter.  The pages of this book are made up of cellulose paper impregnated with with silver nanoparticles.  The silver slowly leaches out of the paper in tiny amounts and is toxic to living microorganisms providing a disinfection benefit capable of granting the user access to safe drinking water.

By combining the pages of the book with an educational component, The Drinkable Book has the power to potentially help address the issue of poor sanitation while also providing safe drinking water.

Friday Five, 2015-08-21


1) Minnesotans are loving their lakes to death.

2) The president of Rio de Janeiro’s water utility acknowledges there are water quality problems with the Olympic event location and says it will be impossible to clear 80% of sewage and waste as the city pledged.

3) An EPA contractor sent tankers of oily water to Shiprock, New Mexico to be used for watering crops and livestock after the mine accident earlier in August contaminated the drinking water supply, angering Navajo Nation officials.

4) American’s don’t pay the true cost of water so when it comes to replacing aging infrastructure it’s hard to gather the funds.  In California, the Department of Water and Power is trying to raise the rate of water by 18% in order to speed up pipe replacement so less water is lost through water mains breaks and leaks.

5) Research is being conducted at Mira Winery in Napa, California, to understand the effects of wine aged under water versus on land.  The impact is called “aquaoir” and so far the results for underwater aging are very promising.

(Photo credit: Kristen Brastad, Skógafoss Waterfall in Iceland)

Page 1 of 2

Powered by WordPress & Theme by Anders Norén