Saturday, July 02, 2016

How do I test my own tap water: a DIY guide (part 1)

I had received queries about testing one's tap water without going through the hassle of sending water samples to a lab i.e. the DIY route.

If at all possible, get a water quality report from your water utility company first. This will save you a lot of trouble and perhaps even eliminate the need for DIY water testing.

I believe it is a requirement of water utilities in the United States to provide one to the consumer. However, here in Singapore, we do not have such a luxury. If you express concern about the safety of your tap water, the one and only water utility (PUB) here will respond and send a staff down to your place to collect samples. When your report comes in, it will state safe or unsafe. (I suppose if it is unsafe, they will do further tests and probably act to rectify the problem.) Nowhere in your "report" will  you see the water quality parameters measured and what their values are.

And you want to take matters into your own hands, testing your water DIY is possible. However, the average consumer will be lost and not know where to start. Hopefully, this post will clarify your doubts and give you the confidence to go ahead.

Here, I assume that you are getting your drinking water from the tap. If your water source is a well, surface water body (e.g. pond, river) or others, you may want to check out my previous posts pertaining to a rural setting.

In another post, I actually provided several vendors in Singapore supplying water quality testing equipment. I did not touch on what parameters to check though. also, these vendors tend to deal with businesses and organisations, rather than the average Joe end user.

This previous post suggested the use water testing strips which is still my stand for the average consumer venturing into the world of water quality testing. I will continue with this idea in this discussion. But please be aware of their limitations as given in my post.

What am I suppose to measure?
Without reinventing the wheel, I have taken a leaf out the U.S. EPA (Environment Protection Agency) for the following table.

Conditions or Nearby Activities:Test for:
Recurring gastro-intestinal illnessColiform bacteria
Household plumbing contains leadpH, lead, copper
Radon in indoor air or region is radon richRadon
Corrosion of pipes, plumbingCorrosion, pH, lead
Nearby areas of intensive agricultureNitrate, pesticides, coliform bacteria
Coal or other mining operations nearbyMetals, pH, corrosion
Gas drilling operations nearbyChloride, sodium, barium, strontium
Dump, junkyard, landfill, factory, gas station or dry-cleaning operation nearbyVolatile organic compounds, total dissolved solids, pH, sulfate, chloride, metals
Odor of gasoline or fuel oil, and near gas station or buried fuel tanksVolatile organic compounds
Objectionable taste or smellHydrogen sulfide, corrosion, metals
Stained plumbing fixtures, laundryIron, copper, manganese
Salty taste and seawater, or a heavily salted roadway nearbyChloride, total dissolved solids, sodium
Scaly residues, soaps don’t latherHardness
Rapid wear of water treatment equipmentpH, corrosion
Water softener needed to treat hardnessManganese, iron
Water appears cloudy, frothy or coloredColor, detergents

Looks lengthy? I have narrowed the list by highlighting those conditions which I believe are more likely in an urban setting.

Here's my list of parameters to test for in tap water

No. Parameter EPH regulations My take
1 E. coli < 1 cfu/100mL An important microbiological indicator. Its presence indicates a high probability of contamination from human fecal matter
2 pH 6.5-9.5 Though pH is not a chemical substance, its deviation from the regulated range indicates a  problematic water that deserves further investigation. Anyway, it is so simple to measure, nobody should forgo its testing.
3 Lead 10ug/L Commonly leached from lead piping and fittings in older installations. It causes serious bodily harm so I consider it a priority for testing.
4 Copper 2mg/L Commonly leached from copper piping and fittings. Though less toxic than lead (notice the value in mg/L instead of ug/L), it can cause complications in people with compromised health.
5 Electrical conductivity (EC) - No value given by EPH or WHO. I suggest using the range in PUB water as a guideline: 92-527 uS/cm

Like pH, EC is not a chemical substance. However its deviation from the normal range should warrant further investigation.
6 Hydrogen sulfide - Not measured in PUB's standard water quality report. And I suggest this be measured only you observe foul smells from the water. A concentration above 0.5mg/L should be enough to produce observable smell.
7 Iron - No value given by EPH or WHO as iron is typically not toxic in normal concentrations. However, it can cause staining on clothing and materials. If you have such an occurrence, you may want to measure it. I suggest using the range in PUB water as a guideline: <0 .003-0.013mg="" font="">
8Manganese0.4mg/LUpdate by author: (For some reason, this row as missed out in copying over.) Manganese is typically not toxic in normal concentrations. However, it can cause staining on clothing and materials. If you have such an occurrence, you may want to measure it. 
  • * Environmental Public Health (EPH) (Quality of Piped Drinking Water) Regulations 2008 are based on WHO guidelines for drinking water quality.
  • For some reason, PUB tends to change its web addresses a bit. The latest report with the EPH values can be found here.

  • I would say that parameters 1, 2, 3, 4 are the basic ones you should measure. If you have a bit more money to spare, EC (parameter 5) should be part of your routine too.
  • Hydrogen sulphide is only necessary if you smell foul odours.
  • Iron and manganese should be measured if you find stain on clothing or other materials.

I will make my recommendation for DIY testing in a subsequent post. Look out for it!

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