Skip to main content

0 questions
2 posts

Do you have questions about Chlorine?

Log in to ask questions about Chlorine publicly or anonymously.

How has the HWTS Network helped you?

The HWTS Network is turning 20 this year! To celebrate this milestone, we’re collecting stories that will help us to demonstrate the critical role that HWTS plays in SDG 6. 

We want to hear from you.  How has the HWTS Network helped you in your work, project or study?

Your story of success could be:

  • a new connection or collaboration
  • development or implementation of a project thanks to evidence in the Knowledge Base
  • implementation of a new technology thanks to product information or a member recommendation
  • … and more! Anything that the network has helped you with.

We will be collecting testimonials in the month of April. Feel free to respond directly to this post or send us an email at

What are the safe levels of chlorine in drinking water?

During the webinar on "A water professional’s guide to safe storage', due to time constraint, the speakers could not answer or discuss with all the participants the questions raised. 

If you missed this webinar, please find it here. 

Interesting question from the webinar: what are the safe levels of chlorine in drinking water?

Here is a list of recommendations on the doses by studies and international guidelines:

  1. Lantagne (2008): 2.0mg/L free chlorine for water with turbidity <10 NTU / 4.0mg/L free chlorine for water with turbidity 10-100 NTU. ("these doses are considered suitable for household water treatment to maintain a free chlorine residual of 0.2 mg/l in stored household water treated by chlorination" - Guidelines for drinking water, WHO)
  2. WHO: 5.0 mg/L at the point of distribution
  3. WHO:  Find the dose to reach at least 0.5 mg/L free chlorine residual  at 30 min after dosing (WHO, 2005)

Do you know any other guideline or study? Any regulation on chlorination in effect in your country?


Brian Reed
Freelance WASH trainer

Can I ask why you need to know? 

if you are treating water, you also need to know the concentration of chlorine- which varies between products and over time.

it is preferable to test the water that needs to be treated on a regular basis and use the amount of disinfectant from the test rather than trying to calculate it. The frequency of testing will depend on the amount of water being treated and the quality of the raw water.