You will need to pay a subscription to the EPMU when you join. If the EPMU has negotiated a collective agreement that covers your work, your employer will deduct the subscription from your salary or wages and pay it directly to the union.
There are other forms of payments that can be made, like direct debit or quarterly or annual payments, if wage deductions are not possible.
Your fee goes towards making sure the EPMU is run effectively to get the best return for members by way of fair wages and conditions, regular pay increases, better health and safety and more job security.
On unionised jobs in the past year, the average annual wage increase bargained as part of collective agreement negotiations was about three times the annual union fee. Not a bad return - and that's just in wage increases.