diff --git a/Makefile b/Makefile
index 1cb9cc5..479f428 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,9 @@ SHELL         = /bin/bash
 # Containers run as the current user rather than root (so that created files are not root-owned)
 DC_OPTS?=--rm -u $(shell id -u):$(shell id -g)
 
+DC_USER?="openmaptiles"
+DC_PASSWORD?="openmaptiles"
+
 # If set to a non-empty value, will use postgis-preloaded instead of postgis docker image
 USE_PRELOADED_IMAGE?=
 
@@ -101,7 +104,7 @@ init-dirs:
 
 build/openmaptiles.tm2source/data.yml: init-dirs
 	mkdir -p build/openmaptiles.tm2source
-	$(DOCKER_COMPOSE) run $(DC_OPTS) openmaptiles-tools generate-tm2source openmaptiles.yaml --host="postgres" --port=5432 --database="openmaptiles" --user="openmaptiles" --password="openmaptiles" > $@
+	$(DOCKER_COMPOSE) run $(DC_OPTS) openmaptiles-tools generate-tm2source openmaptiles.yaml --host="postgres" --port=5432 --database="openmaptiles" --user="$DC_USER" --password="$DC_PASSWORD" > $@
 
 build/mapping.yaml: init-dirs
 	$(DOCKER_COMPOSE) run $(DC_OPTS) openmaptiles-tools generate-imposm3 openmaptiles.yaml > $@