Based on the EPA assessment, we note that the Rfd for Chlorine in drinking water is 0.14 mg/kg of Body weight/day. This is obtained as NOAEL is 14.4 mg/kg of Body Weight/day and we divide the NOAEL by 100 Uncertainty factors, and hence the final amount for Rfd = 0.144 mg/Kg of body weight/day. As Chlorine does not seem to have any cancerous health effects, hence we have not estimated any slope factor. for any cancer. 

Step 4: Exposure assessment

In order to assess the exposure that an a member of a household who consumes the water supplied by the City council is exposed to, we will refer to the Christchurch city council website to find out the amount of chlorine dissolved in the drinking water and the corresponding level.
According to the Christchurch City council website, the current state of chlorination of water in the city of Christchurch is 0.5 ppm (see https://ccc.govt.nz/services/water-and-drainage/water-supply/water-chlorination#4/-54.54/167.70). This is equivalent of 0.5 mg/L by using the following conversion formula (see https://www.rapidtables.com/math/number/PPM.html#mg%20to%20ppm)