Public Health: Water Chemistry Testing
Tarrant County Public Health
Tarrant County Public Health
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{Tarrant County Public Health - Safeguarding Our Community}

Environmental/Consumer Protection

Water Chemistry Testing

Sample Requirements

{Whats in Your Water?}

Time constraints

Samples for chemistry testing are accepted Monday-Friday from 8:00 AM to 2:00 PM.

All samples should be received in the lab within 24 hours of the sample collection time.  Some tests have critical time constraints.

Hydrogen sulfide:  Deliver to the lab as soon as possible after sample collection, preferably within one hour.  Fill the container to overflowing, with no air space at the top.  Cap with a tight fitting lid.  Ideally, H2S is tested at the source.

Chlorine:  Deliver to the lab within 4 hours of sampling.

Lead Analysis:  To detect maximum possible lead contamination, the water sample should be collected after the water has not been used for at least 8 hours, but no longer than 18 hours.  For example, the water may be collected first thing in the morning, if the water has not been running through the night.

Sample containers

Containers must be clean and free of any residue from former contents.  A small amount of residual milk, bleach, orange juice, etc. will alter test results.  Plastic containers are preferred, and should have a secure lid.

Sample volume

Approximately 8 ounces is needed per test.  A one gallon container is adequate to do all 22 chemistry tests available.

Sample identification

Water samples must have the name of the owner, or the submitter on the container.

For best results, the water for pH testing should be collected and tested on
the same day
. If possible, all samples should be kept cool until they are brought to the lab.

Test Significance

Many minerals and contaminants in water may be harmful to health, especially if the exposure occurs over long periods of time. Substances creating a health risk may be bacterial or chemical in nature. For detailed information about bacterial testing, please refer to our water bacteriology pamphlet.

The Tarrant County North Texas Regional Laboratory offers chemical analysis that includes 23 tests, which may be requested individually or as a complete panel. These tests may be categorized as:

  1. those affecting health; and
  2. those creating practical or aesthetic problems

Health Considerations


High levels are most dangerous to children age one and under. Excessive levels of nitrate may react with hemoglobin in the blood to produce "blue baby" syndrome. Nitrate is an oxidized form on nitrogen that may be produced by bacteria converting nitrites to nitrates. High levels of nitrates in water may indicate biological wastes in the final stages of stabilization, or run off from heavily fertilized fields. The Texas Commission on Environmental Quality (TCEQ) and EPA set the maximum contamination level for nitrates at 10mg/L.


Nirites are an intermediate stage in the decomposition of compounds containing nitrogen. Nitrites easily convert to nitrates in the presence of oxygen, so that nitrites are rarely found in surface water. Water containing large amounts of nitrite indicates that the water contains partially decomposed organic matter. Some home loan agencies require nitrite testing as part of the inspection process.


Excessive lead levels in the body can cause serious damage to the brain, nervous system, kidneys, and red blood cells. Young children are especially vulnerable to lead poisoning. Most lead in household water comes from the plumbing rather than the water supply. Plumbing installed before 1930 is likely to contain lead. Newer copper pipes are frequently soldered with lead; in fact, lead solder is thought to be the leading cause of lead contamination in U.S. home water supplies. New brass faucets and fittings can also leach lead, even if they are called "lead free". Any factors that increase water corrosivity increase lead leaching off plumbing into the water. If the water is not corrosive, mineral deposits gradually coat pipe interiors, insulating the water from lead solder. This explains why new homes have a higher risk of lead contamination during the first five years, before any minerals have built up on the plumbing.

To reduce your risk of lead exposure in drinking water:

  1. Only drink from the cold water faucet, since hot water is likely to contain a higher lead level
  2. Flush the tap to be used until it runs as cold as it will get, especially if the water has not been used for six hours or longer.


In addition to adversely affecting the taste of water, high sulfate levels can have a strong laxative effect, especially on people not used to water with increased sulfate levels. Concentrations above 200 mg/L also increase the amount of lead leached from lead pipes. The EPA has set acceptable sulfate levels at 250 mg/L or less.


The EPA guideline for drinking water sodium is 20 mg/L. This is a very low level, chosen because long term exposure may increase blood pressure in susceptible individuals. Excessive sodium may also produce a salty taste. The World Health Organization has a maximum contaminant level (MCL) of 200 mg/L for sodium. TNRCC does not currently have a standard for sodium.


Fluoride occurs naturally in some ground waters. Public water supplies are generally supplemented with fluoride to maintain a level of 1 mg/L and aid in the prevention of dental caries. Fluoride levels of 2 mg/L may cause a brownish discoloration of the teeth, while levels of 4 mg/L or greater are considered toxic and associated with skeletal damage. Fluoridation is controversial. While studies have shown fluoride to decrease the incidence of tooth decay, other studies link fluoridation with increased rates of bone and joint disease.


Drinking water normally contains low concentrations of copper, with concentrations over 1 mg/L producing a bitter taste. High levels of copper are toxic and may be associated with gastrointestinal distress and Wilson's disease. High copper levels also contribute to plumbing corrosion and porcelain staining.

Calcium, Magnesium & Total Hardness

Water hardness is caused by dissolved minerals, mainly calcium and magnesium, but ions of iron, zinc, manganese, etc. may also be present. Excessively hard water limits the effectiveness of soaps and detergents, and may build up as a coating in plumbing.

Low water hardness is associated with an increased risk of cardiovascular disease, perhaps due to deficiencies of calcium and magnesium.

Practical & Aesthetic Considerations


pH is a measure of hydrogen ion activity in a solution. pH 7 is neutral, while pH's below 7 are acidic, and those above 7 are basic. TCEQ's standard for pH in Texas water is pH 7 or greater. EPA's pH guideline is 6.5 - 8.5. pH's below 6.5 are corrosive.


Alkalinity is a measure of the capacity of water to neutralize acids. Alkalinity is primarily due to the presence of bicarbonate, carbonate, and hydroxide ions. Salts of weak acids may also contribute, such as silicates. Alkalinity acts as a pH buffer and must be considered in selecting the appropriate water treatment process. Alkalinity may also affect water taste.

Total Solids

Total Solids are a measure of matter dissolved in water. It is a general test of water quality, usually reflecting mineral content. Water with a high total solid content may be unpalatable and aesthetically unsuitable for bathing. The effectiveness of soaps and detergents may also be compromised. A limit of 500 mg/L of dissolved solids is desirable for drinking water.


Conductivity measures the ability of an aqueous solution to carry an electrical current. This measurement is a gauge of the concentrations of ions present. It is a general, non-specific measure of mineral content and general water quality. Most safe drinking water in the USA has a conductivity of 50 to 1500 µohms/cm.


Iron may be present in our domestic water due to leaching of natural deposits or iron-bearing industrial waste. Iron is generally more of a nuisance than a health hazard. Iron levels greater than .1 mg/L may result in a bitter taste. High levels also cause the staining of laundry and porcelain.


Silica is the second most abundant element in nature. Silica is added to water as a water conditioner and corrosion inhibitor. Silica can cause problems in industry, forming glassy deposits on tubes of boilers and heat exchangers. Measuring silica in water is useful when efficiency of demineralizers is being monitored, as silica is one of the first impurities detected when the exchange capacity of a demineralizer is exhausted.


Chloride is an element considered essential to the human diet. Chlorides are present in all water supplies, usually as chloride ions. Concentrations of chloride over 250 mg/L may give water a salty taste, but high chloride levels are not known to have any toxic effects on humans. However, high chloride levels may harm metallic pipes and plants.

Chlorine is a chemical disinfectant used in water treatment. It is also used for its bleaching ability and odor control. Fort Worth city water typically reaches its customers with a residual chlorine level of about .5 mg/L. Residual chlorine dissipates over a matter of a few hours.

Chlorine gas is irritating to the respiratory tract and mucous membranes. Its odor is detectable at 3.5 parts per million (ppm). Used in high concentrations during World War I in chemical warfare, chlorine gas is fatal at 1,000 ppm. Carefully used as an additive to our drinking water, chlorine protects us from harmful microorganisms.

Water Testing Fees

Description Fee EPA Drinking Water Standard
Alkalinity (Phenol) $10.00 No Standard Established
Alkalinity (Total) $10.00 No Standard Established
Bicarbonate $10.00 No Standard Established
Calcium $10.00 No Standard Established
Carbonate $10.00 No Standard Established
Chloride $10.00 Limit: 250mg/L
Copper $20.00 Limit: 1.0 mg/L
Fluoride $10.00 Limit: 2.0 mg/L
Hardness $10.00 < 60 mg/L = Soft;
> 120 mg/L = Hard
Hydrogen Sulfide $20.00 TCEQ limit 0.05 mg/L
Iron $15.00 Limit: 0.3 mg/L
Lead $25.00 Limit: 15 µg/L
Magnesium $10.00 No Standard Established
Nitrate $15.00 Limit: 10 mg/L
Nitrite $15.00 Limit: 1.0 mg/L
pH $10.00 6.5 - 8.5
Silica $20.00 No Standard Established
Sodium $15.00 Guideline: 20 mg/L
Sulfate $20.00 Limit: 250 mg/L
Total Solids $10.00 Limit: 500 mg/L
Chemistry Panel $220.00  
DPD Chlorine $10.00 No Standard Established
(100 ml sample required)
Conductivity $10.00 No Standard Established
(100 ml sample required)
Duplicate Record $5.00 Per report

Water for Hydrogen Sulfide testing must be submitted immediately after collection, with no air space at the top of the container. Samples for chlorine testing should be received within 4 hours of collection.
All other tests should be received in the lab the same day the water is collected

Questions? Please call 817-321-4750, or 817-321-4776

Content Last Modified on 5/31/2011 1:39:56 PM

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