diff --git a/linux-setup.sh b/linux-setup.sh
index 2b7b198..d892a48 100755
--- a/linux-setup.sh
+++ b/linux-setup.sh
@@ -247,6 +247,24 @@ install_watchman() {
     fi
 }
 
+install_postgresql() {
+    # Instructions taken from
+    # https://pgdash.io/blog/postgres-11-getting-started.html
+    # Postgres 11 is not available in 18.04, so we need to add the pg apt repository.
+    curl -s https://www.postgresql.org/media/keys/ACCC4CF8.asc \
+        | sudo apt-key add -
+
+    sudo add-apt-repository -y "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -c -s`-pgdg main"
+    sudo apt-get update
+    sudo apt-get install -y postgresql-11 postgresql-contrib libpq-dev
+
+    # Set up authentication to allow connections from the postgres user with no
+    # password. This matches the authentication setup that homebrew installs on
+    # a mac. Unlike a mac, we do not need to create a postgres user manually.
+    sudo cp -av postgresql/pg_hba.conf "/etc/postgresql/11/main/pg_hba.conf"
+    sudo service postgresql restart
+}
+
 setup_clock() {
     # This shouldn't be necessary, but it seems it is.
     if ! grep -q 3.ubuntu.pool.ntp.org /etc/ntp.conf; then
@@ -288,5 +306,6 @@ install_protoc
 install_watchman
 setup_clock
 config_inotify
+install_postgresql
 
 trap - EXIT
diff --git a/mac-setup.sh b/mac-setup.sh
index f644dbc..9d079c7 100755
--- a/mac-setup.sh
+++ b/mac-setup.sh
@@ -281,6 +281,25 @@ install_node() {
     fi
 }
 
+install_postgresql() {
+    if ! brew ls postgresql >/dev/null 2>&1; then
+        info "Installing postgresql\n"
+        brew install postgresql@11
+    else
+        success "postgresql already installed"
+    fi
+
+    # We create a postgres user locally that we use in test and dev.
+    if ! psql \
+      -tc "SELECT rolname from pg_catalog.pg_roles"  postgres \
+      | grep -c 'postgres' > /dev/null 2>&1 ; then
+        info "Creating postgres user for dev\n"
+        psql --quiet -c "CREATE ROLE postgres LOGIN SUPERUSER;" postgres;
+    else
+        success "postgres user already created"
+    fi
+}
+
 install_nginx() {
     info "Checking for nginx\n"
     if ! type nginx >/dev/null 2>&1; then
@@ -343,7 +362,7 @@ install_protoc() {
 }
 
 install_watchman() {
-    if ! which watchman ; then
+    if ! which watchman >/dev/null 2>&1; then
         update "Installing watchman..."
         brew install watchman
     fi
@@ -431,6 +450,7 @@ install_homebrew
 install_slack
 update_git
 install_node
+install_postgresql
 install_nginx
 install_image_utils
 install_helpful_tools
diff --git a/postgresql/pg_hba.conf b/postgresql/pg_hba.conf
new file mode 100644
index 0000000..87f8388
--- /dev/null
+++ b/postgresql/pg_hba.conf
@@ -0,0 +1,13 @@
+# We allow any connection by the postgres user to local addresses, without a
+# password.
+
+# TYPE  DATABASE        USER            ADDRESS                 METHOD
+# "local" is for Unix domain socket connections only
+local   all             postgres                              trust
+
+# IPv4 local connections:
+host    all             postgres      127.0.0.1/32            trust
+# IPv6 local connections:
+host    all             postgres      ::1/128                 trust
+
+
diff --git a/setup.sh b/setup.sh
index d99d5b5..e123586 100755
--- a/setup.sh
+++ b/setup.sh
@@ -318,6 +318,13 @@ download_db_dump() {
     fi
 }
 
+create_pg_databases() {
+    if [ "$WEBAPP" = true ]; then
+        echo "Creating postgres databases"
+        ( cd "$REPOS_DIR/webapp" ; make pg_create )
+    fi
+}
+
 # Make sure we store userinfo so we can pass appropriately when ka-cloning.
 update_userinfo() {
     echo "Updating your git user info"
@@ -393,6 +400,7 @@ install_deps        # pre-reqs: clone_repos, install_and_setup_gcloud
 install_hooks       # pre-req: clone_repos
 setup_arc           # pre-req: clone_repos
 download_db_dump    # pre-req: install_deps
+create_pg_databases # pre-req: install_deps
 
 
 echo