The process of electrochlorination is a simple application based on the chloralkali process (in an unpartitioned cell). 
It is the electrolysis of saltwater to produce a chlorinated solution. The first step is removing any solids from the saltwater. Next, the saltwater streams through an electrolyzer cell's channel of decreasing thickness. One side of the channel is a cathode, the other is an anode. A low voltage DC current is applied, electrolysis happens producing sodium hypochlorite and hydrogen gas (H). The solution travels to a tank that separates the hydrogen gas based on its low density. Only water and sodium chloride are used. The simplified chemical reaction is:
:NaCl + HO + energy → NaOCl + H
That is, energy is added to sodium chloride (table salt) in water, producing sodium hypochlorite and hydrogen gas. 
Because the reaction takes place in an unpartitioned cell and NaOH is present in the same solution as the Cl:
:2 NaCl + 2 HO → 2 NaOH + H + Cl
any Cl disproportionates to hypochlorite and chloride
:Cl + 2 NaOH → NaCl + NaClO + HO
resulting in a hypochlorite solution.