In the water business testing for free chlorine happens quite frequently (as Scott just said)… and we know of two ways to make that task easier:

• DPD ReagentStrips — If you use DPD-1 to test for free chlorine residual, then undoubtedly you do so using DPD in powder or tablet form. Both methods work, but DPD-1 ReagentStrips make testing for free chlorine residual in water a faster and easier process while staying in compliance with 4500-CL G. Simply insert a DPD-1 ReagentStrip into a 10mL water sample, move it back and forth (liberated required DPD chemistry off of reagent pads), and read visually or with your favorite meter.
   
• SenSafe™ Free Chlorine Water Check — In the original recommendation letter from the USEPA, dated October 2003: “We believe that the ITS test strips will provide the regulatory community with a valuable option for monitoring free chlorine levels in drinking water.” This method bears USEPA Approval for in drinking water applications.

While both testing methods make free chlorine residual testing much easier without losing accuracy, we highly suggest check with your State and Local inspectors first before using either product for compliance monitoring… because as you know (probably better than we do!), sometimes State/Local regulation changes do not always keep up with Federal Regulation changes.

We do not know of an International Standard for free chlorine levels in irrigation water but we do know that most States in the US require wastewater treatment plants to neutralize TOTAL chlorine levels before discharging water into the environment and that wastewater treatment facilities must test for total chlorine residuals in their effluent streams on a regular basis to make sure the chlorine concentrations stay virtually non-existent.

Why worry about chlorine in the environment?

If allowed to enter the environment chlorine can and will effectively kill or damage biological organisms that it comes in contact with. In great enough concentrations chlorine will wipe out all plant life in a body of water as well as any animals or fish in the water.

We use chlorine to render safe (i.e. KILL) biological contaminants in our drinking water and if released into a natural habitat the chlorine will render safe (i.e. KILL) any and all plant an animal life until it loses its effectiveness.

Testing for free & total chlorine?

Whether you prefer test strips, wet chemistry kits or a water testing meter… you have plenty of choices when it comes to testing for both free and total chlorine levels in drinking and treated waste water.

Determining the Chlorination System Your Water Supplier Uses

Chlorine Smell Test: In general, water containing only chloramines gives off a much more objectionable odor than water containing a free chlorine residual. While true that a free chlorine system generates chloramines as the free chlorine gets used up fighting whatever biological contaminants it encounters, the amount of odor given off by those chloramines will typically not surpass the amount of odor given off by water treated solely with chloramines.

Home Water Testing: While no test strip exists to check JUST the chloramine concentration in water, one does exist to check both the Free Chlorine Residual and the Total Chlorine Residual: The WaterWorks^tm 2 Free & Total Chlorine Strip accurately measures both parameters with a single water quality test strip.

WaterWorks^tm 2 Free and Total Chlorine Home Water Test Kit

• If the free chlorine test area shows color AND the total chlorine test area shows color, then your water supplier most likely uses free chlorine as its primary disinfectant.

• If the free chlorine test area does not show color BUT the total chlorine test area does not show color, then your water supplier most likely uses chloramines as its primary disinfectant.

Although the above testing method will yield quality results, calling your local water supplier will get you the same information.

Should you wish to test for the presence of just free chlorine or just total chlorine in drinking water, the following simple test strips will yield fast, accurate and reliable results in under a minute:

• Total Chlorine Test Strip (480010)
• Free Chlorine Test Strip (481026)

(Free Chlorine) + (Combined Chlorine) = (Total Chlorine)

Free Chlorine: Typically your main sanitizing/disinfecting agent and sometimes referred to as ‘available chlorine’. In most cases people try to keep a free chlorine residual in their water to act as a buffer against biological contaminants. Chemically speaking this is the amount of hypochlorous acid and hypochlorite ion in solution. find free chlorine test strips

Combined Chlorine: The resulting compound when free chlorine molecules interact with biological contaminants containing Nitrogen which most people refer to as ‘chloramines’. You could also refer to combined chlorine as ‘used free chlorine’, but keep in mind that it still does have the abiity to act as a sanitizer/disinfectant… just not nearly as effectively.  find total chlorine test strips

Total Chlorine: The sum of all free, ‘available’, combined, and ‘used’ chlorine in solution.  find total chlorine test strips

Testing for Free & Total Chlorine at the Same Time?

The traditional testing method for chlorine residuals in water involves the use of a reagent system known as DPD that involves two separate chemical mixing procedures.

The WaterWorks 2 Free & Total Chlorine Test Strips have a total test time of around 30 seconds and detect both free and total concentrations in water in the following range: 0, 0.1, 0.2, 0.5, 1, 1.0, 2.5, 5.0 ppm.

If you need to test chlorine levels in your water, then we definitely suggest checking out the chlorine testing convenience and affordability of WaterWorks 2 Free & Total Chlorine Test Strips.