diff --git a/src/Database/Postgres/Temp/Internal/Partial.hs b/src/Database/Postgres/Temp/Internal/Partial.hs
--- a/src/Database/Postgres/Temp/Internal/Partial.hs
+++ b/src/Database/Postgres/Temp/Internal/Partial.hs
@@ -52,7 +52,7 @@
 --   inherit from the running process or they
 --   can be specifically added.
 data PartialEnvVars = PartialEnvVars
-  { partialEnvVarsInherit  :: Bool
+  { partialEnvVarsInherit  :: Last Bool
   , partialEnvVarsSpecific :: Map String String
   }
   deriving stock (Generic, Show, Eq)
@@ -60,21 +60,22 @@
 instance Semigroup PartialEnvVars where
   x <> y = PartialEnvVars
     { partialEnvVarsInherit  =
-        partialEnvVarsInherit x || partialEnvVarsInherit y
+        partialEnvVarsInherit x <> partialEnvVarsInherit y
     , partialEnvVarsSpecific =
         partialEnvVarsSpecific y <> partialEnvVarsSpecific x
     }
 
 instance Monoid PartialEnvVars where
-  mempty = PartialEnvVars False mempty
+  mempty = PartialEnvVars mempty mempty
 
 -- | Combine the current environment
 --   (if indicated by 'partialEnvVarsInherit')
 --   with 'partialEnvVarsSpecific'
-completePartialEnvVars :: [(String, String)] -> PartialEnvVars -> [(String, String)]
-completePartialEnvVars envs PartialEnvVars {..}
-  =  if partialEnvVarsInherit then envs else []
-  <> Map.toList partialEnvVarsSpecific
+completePartialEnvVars :: [(String, String)] -> PartialEnvVars -> Either [String] [(String, String)]
+completePartialEnvVars envs PartialEnvVars {..} = case getLast partialEnvVarsInherit of
+  Nothing -> Left ["Inherit not specified"]
+  Just x -> Right $ (if x then envs else [])
+    <> Map.toList partialEnvVarsSpecific
 
 -- | A type to help combine command line arguments.
 data PartialCommandLineArgs = PartialCommandLineArgs
@@ -142,7 +143,7 @@
 standardProcessConfig :: PartialProcessConfig
 standardProcessConfig = mempty
   { partialProcessConfigEnvVars = mempty
-      { partialEnvVarsInherit = True
+      { partialEnvVarsInherit = pure True
       }
   , partialProcessConfigStdIn  = pure stdin
   , partialProcessConfigStdOut = pure stdout
@@ -164,8 +165,9 @@
 completeProcessConfig
   :: [(String, String)] -> PartialProcessConfig -> Either [String] ProcessConfig
 completeProcessConfig envs PartialProcessConfig {..} = validationToEither $ do
-  let processConfigEnvVars = completePartialEnvVars envs partialProcessConfigEnvVars
-      processConfigCmdLine = completeCommandLineArgs partialProcessConfigCmdLine
+  let processConfigCmdLine = completeCommandLineArgs partialProcessConfigCmdLine
+  processConfigEnvVars <- eitherToValidation $
+    completePartialEnvVars envs partialProcessConfigEnvVars
   processConfigStdIn  <-
     getOption "partialProcessConfigStdIn" partialProcessConfigStdIn
   processConfigStdOut <-
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -64,7 +64,6 @@
       extraConfig = "log_min_duration_statement='" <> expectedDuration <> "'"
 
   it "returns the right client options for the plan" $ do
-    let initialCreateDbConfig = standardProcessConfig
     let customPlan = mempty
           { configPlan = mempty
               { partialPlanPostgres = mempty
@@ -74,31 +73,36 @@
                       , Client.dbname   = pure expectedDbName
                       }
                   }
-              , partialPlanInitDb = pure mempty
+              , partialPlanInitDb = pure standardProcessConfig
                   { partialProcessConfigCmdLine = mempty
                       { partialCommandLineArgsKeyBased =
                           Map.singleton "--username=" $ Just "user-name"
                       }
-                  , partialProcessConfigEnvVars =
-                      mempty { partialEnvVarsSpecific = Map.singleton "PGPASSWORD" "password" }
+                  , partialProcessConfigEnvVars = mempty
+                      { partialEnvVarsSpecific = Map.singleton "PGPASSWORD" "password"
+                      , partialEnvVarsInherit = pure True
+                      }
                   }
               , partialPlanConfig = [extraConfig]
               }
           }
     -- hmm maybe I should provide lenses
-    let combinedResources = defaultConfig <> customPlan
-        finalCombinedResources = setCreateDb combinedResources $ pure initialCreateDbConfig
+    let createDb = pure standardProcessConfig
           { partialProcessConfigCmdLine = mempty
-          { partialCommandLineArgsKeyBased =
-              Map.singleton "--username=" $ Just "user-name"
-          , partialCommandLineArgsIndexBased =
-              Map.singleton 0 expectedDbName
-          }
+            { partialCommandLineArgsKeyBased =
+                Map.singleton "--username=" $ Just "user-name"
+            , partialCommandLineArgsIndexBased =
+                Map.singleton 0 expectedDbName
+            }
           , partialProcessConfigEnvVars =
-              mempty { partialEnvVarsSpecific = Map.singleton "PGPASSWORD" "password" }
+              mempty
+                { partialEnvVarsSpecific = Map.singleton "PGPASSWORD" "password"
+                , partialEnvVarsInherit = pure True
+                }
           }
+        combinedResources = setCreateDb defaultConfig createDb <> customPlan
 
-    action finalCombinedResources $ \db@DB {..} -> do
+    action combinedResources $ \db@DB {..} -> do
       bracket (PG.connectPostgreSQL $ toConnectionString db) PG.close $ \conn -> do
         [PG.Only actualDuration] <- PG.query_ conn "SHOW log_min_duration_statement"
         actualDuration `shouldBe` expectedDuration
@@ -206,7 +210,7 @@
     let startAction plan = bracket (either throwIO pure =<< startConfig plan) stop pure
     throwsIfInitDbIsNotOnThePath $ startAction defaultConfig
     invalidConfigFailsQuickly $ void . startAction
-    customConfigWork $ \plan f ->
+    customConfigWork $ \plan@Config{..} f ->
       bracket (either throwIO pure =<< startConfig plan) stop f
   describe "with" $ do
     let startAction = either throwIO pure =<< with (const $ pure ())
@@ -360,7 +364,7 @@
               Just host = getLast $ Client.host $ postgresProcessClientConfig dbPostgresProcess
               backupCommand = "pg_basebackup -D " ++ baseBackupFile ++ " --format=tar -p"
                 ++ show port ++ " -h" ++ host
-          putStrLn backupCommand
+
           system backupCommand `shouldReturn` ExitSuccess
 
           bracket (PG.connectPostgreSQL $ toConnectionString db ) PG.close $ \conn -> do
diff --git a/tmp-postgres.cabal b/tmp-postgres.cabal
--- a/tmp-postgres.cabal
+++ b/tmp-postgres.cabal
@@ -1,5 +1,5 @@
 name:                tmp-postgres
-version:             1.3.0.0
+version:             1.4.0.0
 synopsis: Start and stop a temporary postgres
 description:
  @tmp-postgres@ provides functions creating a temporary @postgres@ instance.