Tap water at 20degC only has about 7g of Cl2 dissolved in it per litre as supplied from the tap.
Cf my Perry's Chemical Engineers' HB , solubility constant for Cl2 in water is
2.48x10^-3 @ 283Kelvin
1.88x10^-3 @ 293Kelvin
Easy to remove Cl2 from tap water , simply boil the water then cool it down in the fridge and you'll have Cl2 free water.
As stated above - if your tap water is safe for human use and ingestion, it's safe for your lizards, and it's LOTS cheaper than buying supposedly "pure" bottled water in plastic bottles.
Also read this
http://www.abc.net.au/health/talkinghealth/factbuster/stories/2010/10/27/3048695.htm , you may well be doing more harm than good buying bottled water for your lizards (and self) than you realise as some components of plastic leach out of the plastic and contaminate the water.
If you have a bit of chemistry under your belt (university level) you might find this 2016 research report (thesis) informative
https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/17627/Dornath%20thesis.pdf?sequence=1