Categories Ministerial Decision Ministry of Regional Municipalities and Environment: Ministerial Decision 421/98 Issuing the Regulation of Septic Tanks, Soakaway Pits, and Holding Tanks 1998/421 421/1998 98/421 421/98 Post author By admin Post date November 30, 1998 You do not have access to this page. Please view our subscribe page to learn more about our subscription, or login if you already have an account. Username or E-mail Password Remember Me Forgot Password Tags Ministry of Regional Municipalities and Environment ← Royal Decree 83/98 Amending Some Provisions of Royal Decree 64/83 Establishing the Omani Banking Institute → Royal Decree 90/98 Adopting the Organisational Structure of the Ministry of Social Affairs, Labour, and Vocational Training