The state of Nevada requires all registered motor vehicles to be covered by liability insurance. Minimum coverage of $15,000 for bodily injury or death of one person in any one accident; $30,000 for bodily injury or death of 2 or more persons on any one accident; and $10,000 for damage or destruction of property of others in anyone accident is mandated. This coverage must be reported by an insurance company authorized to do business in Nevada.
As part of the rating system and to give you an accurate quote for your insurance premiums the Division of Insurance allows insurance companies to request information on the description of your vehicle, its use, your drivers license number, number and ages of drivers in your household, the coverage and limits you want and what accidents and tickets you have had in the last 3 to five years.
From this DOI information it would appear that insurance companies in Nevada can rate on accidents for a period of 3 to 5 years. The amount of time that the accident will affect your insurance rates likely depends on the type of accident you were in and your individual insurance company's rating system. You should be able to find out the rating system from your agent or from contacting the NV DOI since insurance carriers file their rates with this state agency.
If your rates are too high due to a previous accident on your record, comparison shop for a Nevada automobile insurance quote.