Soaking rice in water and discarding the water reduces its arsenic content.

Study: Removal of Toxic and Essential Nutrient Elements from Commercial Rice Brands Using Different Washing and Cooking Practices: Human Health Risk Assessment

Washing rice lots of times and cooking it with lots of water, then throwing out the water, takes out a third of the arsenic. So yes, soaking and draining rice helps lower arsenic levels.

Study: An assessment of the impact of traditional rice cooking practice and eating habits on arsenic and iron transfer into the food chain of smallholders of Indo-Gangetic plain of South-Asia: Using AMMI and Monte-Carlo simulation model

If you soak rice in clean water and then throw out that water, you can wash away some of the arsenic, making the rice safer to eat. But if you use dirty water with arsenic, it can make the rice more poisonous.

Study: The reduction of toxic metals of various rice types by different preparation and cooking processes - Human health risk assessment in Tehran households, Iran.

Soaking rice in water for a while and then throwing out the water washes away some of the arsenic, and the longer you soak it, the more arsenic comes out.