Table of Drinking Water Contaminant Levels

Limits of allowable levels of water contaminants:

When testing drinking water the contaminant limits listed here assist in deciding when water purification or other water treatment is needed.

This table provides the allowable limits of various contaminants found in drinking water.

Table of Allowable Limits of Water Contaminants

While the table of water contamination ingredients and allowable levels is from New York State, these limits or similar numbers will apply in most jurisdictions. Water contamination limits and testing requirements in the U.S. are regulated by the Federal Clean Drinking Water act.

Subpart 5-1 of the New York State Sanitary Code defines "Maximum Water Contaminant Level' as the permissible level of a contaminant in water which is delivered to any user of a public water system. New York State does not regulate private drinking water supplies (single family homes on well water).

Most lenders require at least a confirmation of "potable" water meaning that bacteria count and coliform bacteria count is less than 1 CFU per 100 ml. of drinking water in the water test sample. Some lenders require water passing the FHA "Short" or FHA "Long" test list items. Readers of this article should also see Drinking Water Supply, Contamination Levels, Water Testing Procedures.

Notes to the table above

Notes about drinking water contaminant acceptable levels:

(a) mg/L = milligrams per liter

(b) If iron and manganese are present, the total concentration of both should not exceed 0.5 mg/L.

© Water containing more than 20 mg/L of sodium should not be used for drinking by people of severely restricted sodium diets. Water containing more than 270 mg/L of sodium should not be used for drinking by people on moderately restricted sodium diets.

(d) Color test result expressed as Platinum Cobalt Color Units

(e) Odor test result expressed as Threshold Odor Number

(f) If nitrate and nitrite are present, the total concentration of both should not exceed 10 mg/L.

(g) "Action level" is the concentration of lead or copper (in a sample of water drawn from a tap normally used for drinking after a 6-hour period of no water use) that, when exceeded, triggers actions to be taken by a water system.

(h) FHA "Short List" items

(i) FHA "Long List" items - (indications to be added after lab review)

• CT, BACTERIA in PRIVATE DRINKING WATER WELLS [PDF] (2009) Connecticut DOH, adapted from "Healthy Drinking Water for Rhode Islanders", University of Rhode Island Cooperative Extension (2003) - retrieved 2023/10/04, original source: https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/pdf/04BacteriainPrivateDrinkingWaterWells0409pdf.pdf
  
  Excerpt:
  
  If Water Tests Indicate the Presence of Coliform Bacteria
  
  If a water test indicates the presence of coliform bacteria, you should not drink the water or use it for cooking, brushing teeth, etc.
  
  The next step is to attempt to identify and eliminate the source of contamination. If you are unable to locate and eliminate the bacteria source and cannot afford a new well, you may need a long-term treatment method.
  
  Overall, long-term treatment methods may result in being the most expensive alternative due to continuous operation and maintenance costs.
  
  As you attempt to find the source of contamination, evaluate both well location and well construction.
  
  Check the entire water distribution system for potential problem areas, including a garden hose without proper backflow prevention. Well location is a crucial safety factor.
  
  A well that is downhill from a source of bacterial contamination runs a greater risk of contamination that a well on the uphill side of the pollution source.
  
  Good well location requires minimum separation distances from sources of potential contamination, using the natural protection provided by soil filtration. Contact a registered well driller or pump installer for all well maintenance or repairs.
• NB, FACTS on DRINKING WATER: Coliform Bacteria, Total Coliforms & E. Coli [PDF] New Brunswick Department of Health Protection, Woodstock, New Brunswick, 200 King St., New Brunswick Canada, Tel: 506-325-4408, retrieved 2023/10/04, original source: www2.gnb.ca/content/dam/gnb/Departments/h-s/pdf/en/HealthyEnvironments/water/Coliforme.pdf
• US EPA, REVISED TOTAL COLIFORM RULE: A QUICK REFERENCE GUIDE [PDF] (2013) U.S. Environmental Protection Agency - retrieved 2023/10/04, original source: https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100K9MP.txt
  
  Revised Total Coliform Rule (RTCR) 78 FR 10269, February 13, 2013, Vol. 78, No. 30
  Excerpt:
  The RTCR establishes a maximum contaminant level (MCL) for E. coli and uses E. coli and total coliforms to initiate a “find and fix” approach to address fecal contamination that could enter into the distribution system. It requires public water systems (PWSs) to perfor

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

We found a high sodium count in new well, had trouble passing a bacteria test, ran out of water in 15 minutes! Is there a cheap solution?

We have built a new home through a very well known builder. A well was installed and it has been found that there is over 8,000 something of sodium. The well company chlorinated the well 4 times to remove the bacteria. The county has not passed the water.

Also our GPMS was logged as 2 GPMS. Needless to say the water totally cut off after 15 minutes. Now the builder and well drilling company wants us to pay for a whole new well and they can not guarantee that they will not get the same result. We are hoping we have that there can be some resolution that will not cost us!! On 2021-09-16 by Sheila -

Answer by inspectapedia.com.moderator (mod) - new well with poor water quality, contaminants, & very poor recovery rate or flow rate.

@Sheila,

2 GPMS ? Two gallons per second? Really? That would be a stunning flow rate of 120 gallons per minute!

I suspect you meant 2 GPM or two gallons per minute, that would also be unacceptable (insufficient) for most mortgage lenders and not so nice to live-with.

If that's the case you'd want to either take steps to try to increase the yield of the existing well or drill a new one at a different location.

While a geotechnical engineer or similar expert can sometimes map underground water tables, drilling a well is always a bit of a pig-in-a-poke: uncertain.

There's no free lunch, here; the well driller is in no position to promise you what they're going to find when drilling into the ground, nor can they keep drilling wells for free. So I'm not sure of an equitable way for you, the homeowner, to avoid that cost.

Discuss with your well driller the options of trying to improve the present well or drill a new one:

Which has the better chance of improving the well flow rate and at lesser total cost?

Your well driller may be expected to know from experience what water they've been finding at what depths and at what flow rates for wells in your area, but they can't guarantee any specific flow rate in advance.

Watch out: in my OPINON, if we force a contractor to guarantee what is basically an unknown, if the contractor is going to agree to do so, she will have no choice but to set a cost to you that can cover the absolute worst case and thus the most-expensive possible case. That higher cost is sometimes, but not usually, necessary.

Your financial plan for the home will also have to consider the possible cost of water treatment equipment to produce potable water.

You haven't given, and it would be helpful to know, the country and city/province/state of location of the well. You might then also look at the geological and water data for that area.

In our OPINION these well water quantity and quality concerns are only going to get worse in many areas that are becoming much more dry as a result of climate change.

What are "good readings" on water tests for mobile homes?

Please help! I am stumped, how am i getting good readings at my well when im not adding any chlorine and still getting good readings through out all my mobile home rentals? - Smitty Smith 6/28/12

Reply:

Smitty:

What kind of good readings at your well?

If you mean a bacteria test that is not showing any bacterial contamiantion, if the current water coming into your system is not contaminated with bacteria it won't show up, chlorine or not.

...

Continue reading at WELL WATER CONTAMINATION: CAUSES, CURES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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• Watch out: also see WATER TESTING ADVICE for home buyers and building owners: water contaminants, water test procedures, well shock procedures, preventing drinking water contamination, and
  
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