Drinking Water Smells, Smelly Water, Taste 
	and Odor Problems- Threshold Odor Number (TON)
Besides the parameters described in this report, the color, appearance, taste, smell, and odor of drinking water is the first clue to the homeowner that there may be a problem with the water.
	It is important to note that some chemicals, especially organic compounds and bacterial agents, may be at toxic or at pathogenic (i.e., disease causing) levels, without any observable clues to a problem. For this reason, it is recommended that you have your water tested at least annually. Table 1 describes the common water quality problems that may be detectable based on the taste, odor, or appearance.
	
	Primary treatment method used to handle taste, smell, odor, or color  problems may include filtration, filtration through a carbon filter, softening, reverse osmosis, chlorination and distillation. The type of pretreatment would depend on the concentration and type of contamination and associated water quality.
	 
Taste, Smell, Odor, and Color and
Associated Potential Problem
	
	Taste Problems
| Salty-brackish | High sodium | 
| Alkali Taste Oily, Fishy, or Perfume-Like Tase | High hardness, total dissolved solids, high alkalinity Surfactants | 
| Metallic Taste | Low pH, high metal content, corrosive water A metallic taste can be caused by inorganic chemicals such as iron (at levels over 0.004 mg/l), manganese (> 0.1 mg/L) copper (2-5 mg/l), and zinc (4-9 mg/l), nuisance bacteria | 
	
	Odor / Smell Problems Drinking Water
| Rotten-Egg Odor Smell Musty Odors Smell Earthy, musty, grassy, fishy, vegetable and cucumber | Hydrogen sulfide, sulfate-reducing bacteria, Softwater reactions in electric water heaters, algal by-products, bacteria, algal by-products, surfactants | 
| Oily Smell | Gasoline or oil contamination, possibly nuisance bacteria | 
| Methane Like Gas Smell | Organic decomposition - note natural gas has no odor, but the natural gas delivered to your home has mercaptans (sulfur -compounds) added that create a strong odor to help detect leaks. | 
| Phenolic Smell | Industrial or gasoline contamination | 
| Chemical Smell | Organic chemicals, Industrial | 
	
	Color
| Milky | Precipitation of carbonates, excessive air, suspended solids | 
| Blackish Tint | Reactions with manganese and possibly iron, IRB/ Slime Bacteria, anaerobic bacteria | 
| Yellowish Tint | Presence of humic or fluvic compounds, iron, IRB bacteria, anaerobic/aerobic bacteria | 
| Reddish Tint Foam | Presence of  Dissolved or precipitated iron, iron, IRB bacteria,  anaerobic/aerobic bacteria Surfactants - Foaming Agents | 
(Source: Driscoll, 1986; Lehr, 1980; Oram, 1990)
	
	Threshold Odor Numbers- How They Are Determined
	
	Source: Civil Engineering Department of Virginia Tech
	
	TON =  (A + B)/ A
	A - Volume of Sample with odor
	B - Volume of Pure Water with no odor Added
	If A was a 100 ml sample and 100 ml of water had to be added to not detect the odor - the TON would be 2.
	TON =  (100 + 100)/ 100
	 
	
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