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TSS and TDS in the Drinking Water!

Whether your drinking water comes from a water district, a well, or a bottled water plant, safe, high quality water is of utmost concern. Regardless of how your drinking water arrives, it all starts from the same source: our environment. The cleaner and safer the water is in the natural environment, the fewer treatments it must endure before you can (or should) drink it. Fewer treatments means lower costs and healthier water to drink for all. And cleaner, safer water begins with lower levels of both Total Suspended Solids and Total Dissolved Solids - TSS and TDS, two general categories of water contamination. TSS includes all particles in water that can be filtered by a 2 micron filter; TDS includes all particles that will pass unfiltered through that filter and would require more elaborate removal processes. Together they comprise the solid contamination of water, an impurity that needs to be minimized for healthy drinking water..

There are many different types of contaminants that can affect the quality of the water you drink. Some of these contaminants occur naturally, some not. Some are naturally occurring but their levels can be increased through human activities. According the U.S. Environmental Protection Agency, the categories of contaminants that can affect groundwater and drinking water include microorganisms, disinfectants and byproducts of disinfectants, inorganic and organic chemicals, and radionuclides. (See the EPAs website for examples of these types of pollutants for each category:

For surface water, one of the greatest current threats to our drinking water and overall water quality is that of nonpoint source pollution. Nonpoint source pollution (or NPS pollution) is a type of water pollution that does not originate from a specific place but instead from a variety of diffuse sources. Most NPS pollution comes from pollutants being washed into a waterbody by rainfall and snowmelt. As human development and activity increases within a watershed, so doesnt the level of NPS pollution that can potentially affect our water resources. There are a variety of different types of NPS pollution of which among them include:

  • excess sediment from stream bank erosion and improperly managed construction sites;
  • excess nutrients from fertilizer use;
  • both excess nutrients and bacteria from livestock, pet waste and improperly functioning septic systems;
  • toxic chemicals such as oil, grease, and other motor vehicle fluids from road crossings;
  • salt from winter ice melting;
  • herbicides and pesticides from residential and agricultural areas.   

Many of these types of pollution can also contaminate groundwater through seepage, causing concerns to drinking water quality. For example, in Maine and New Hampshire, and throughout the U.S., one type of toxic chemical that is lately of high concern to groundwater is that of methyl tertiary-butyl ether or MTBE. MTBE is an additive to gasoline intended to help reduce automobile emissions and improve air quality. However, this additive, along with gasoline itself, has entered our surface and groundwater through gasoline spills and leaks. In Maine, a 1998 statewide survey determined that 16% of groundwater supplies contained MTBE!

(http://www.umaine.edu/mcsc/Research/EnvPol/MtBE.htm) Like many toxic chemicals in our environment, the complete health effects of them are unknown, yet MTBE has been shown to cause cancer to laboratory animals exposed to large amounts of this chemical

(http://www.maine.gov/dep/rwm/homeowner/mtbe/ques.htm). Due to the potential harm MTBE can have on our drinking water, in 2004 both Maine and New Hampshire (see http://www.des.state.nh.us/mtbe_doclist.htm for a list of documents from New Hampshire concerning MTBE) put a partial ban on the use of MTBE in gasoline. Both states now require that there be no more than .5% MTBE in gasoline sold, in New Hampshire , this also includes other gasoline ethers including tertiary butyl alcohol (TBA).

(http://www.epa.gov/otaq/consumer/fuels/mtbe/mtbe.htm#reformulated )


Arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, and zinc are other types of toxics that are known to negatively impact groundwater used for drinking. All of these metals can occur naturally in groundwater yet their levels can also increase from human activities. For a list of the drinking water standards for these metals and their sources in Maine, please visit the Maine Department of Health and Human Services website at http://www.maine.gov/dhhs/etl/wtrfc2.htm

 or the New Hampshire DES at http://www.des.state.nh.us/wseb/.

In addition to groundwater contaminants, there is also the threat of salinization. Salinization of groundwater occurs when coastal groundwater is pumped low enough with constant freshwater recharge causing ocean water to seep in. An increase in the waters salinity can make it unpleasant to drink and too expensive to treat.


How contaminated a water body is, and what it is contaminated with, can affect the cost of treating the water. Virtually all the water we drink has been treated in some manner before we drink it. For local municipal water districts, there is a constant balance of identifying contaminant levels and then treating for contaminants that exceed human drinking water safety guidelines. In the Merriland River, Branch Brook, and Little River watershed in Kennebunk, Wells, and Sanford, Maine, the Kennebunk, Kennebunkport, and Wells Water District (KKWWD) is constantly adjusting for contaminant influxes in its water supply the Branch Brook. Since KKWWDs main water supply is from a surface water source, NPS pollution is one of its key concerns. In recent years, KKWWD has had to deal with treating excess TSS within its water. The exact source of the excess sediment is unclear, but is most likely due to NPS pollution. Causes of excess sediment are most likely to occur from bank erosion or loss of vegetation around the Brook. For KKWWD, treating this excess sediment in its water to meet basic water quality standards has become so great that they have been looking into alternative water sources. Either way, treating the current source or growing to find new sources, these efforts are a cost that is indirectly paid by the citizens drinking this water. To further explore how an ecosystem service, such as the Branch Brook or water resources in general, are linked to economics, you can read SWIMs Water Economics article.


Our water resources are the most important and valuable resource out there. They are essential to survival and clean water is highly valuable to our quality of life. Although water districts, well test kits, and bottling plants can monitor a variety of water contaminants, its impossible to monitor or even know, let alone treat, all of the contaminants that are out there. Even the long term health effects of many of these contaminants are unknown and many have yet to be determined. Given all of these factors, it is safe to say that best policy to treating our drinking water is to protect it to the best of our abilities from contamination in the first place. As human development and activities increase within the Seacoast area, protecting our water resources becomes critical.

The Wells National Estuarine Research Reserve at Laudholm Farm, Wells, Maine Copyright 2006 All rights reserved. Collaboration with NOAA CSC, Charleston SC