diff --git a/app/vmalert/README.md b/app/vmalert/README.md
index 3b1df81030..77d01a160b 100644
--- a/app/vmalert/README.md
+++ b/app/vmalert/README.md
@@ -166,8 +166,10 @@ The shortlist of configuration flags is the following:
     	Optional basic auth password for -datasource.url
   -datasource.basicAuth.username string
     	Optional basic auth username for -datasource.url
- -datasource.lookback duration
+  -datasource.lookback duration
         Lookback defines how far to look into past when evaluating queries. For example, if datasource.lookback=5m then param "time" with value now()-5m will be added to every query.
+  -datasource.maxIdleConnections int
+        Defines the number of idle (keep-alive connections) to configured datasource.Consider to set this value equal to the value: groups_total * group.concurrency. Too low value may result into high number of sockets in TIME_WAIT state. (default 100)
   -datasource.tlsCAFile string
     	Optional path to TLS CA file to use for verifying connections to -datasource.url. By default system CA is used
   -datasource.tlsCertFile string
diff --git a/app/vmalert/datasource/init.go b/app/vmalert/datasource/init.go
index 89814dde59..62e7848eb0 100644
--- a/app/vmalert/datasource/init.go
+++ b/app/vmalert/datasource/init.go
@@ -24,6 +24,8 @@ var (
 
 	lookBack = flag.Duration("datasource.lookback", 0, "Lookback defines how far to look into past when evaluating queries. "+
 		"For example, if datasource.lookback=5m then param \"time\" with value now()-5m will be added to every query.")
+	maxIdleConnections = flag.Int("datasource.maxIdleConnections", 100, "Defines the number of idle (keep-alive connections) to configured datasource."+
+		"Consider to set this value equal to the value: groups_total * group.concurrency. Too low value may result into high number of sockets in TIME_WAIT state.")
 )
 
 // Init creates a Querier from provided flag values.
@@ -36,6 +38,7 @@ func Init() (Querier, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to create transport: %w", err)
 	}
+	tr.MaxIdleConns = *maxIdleConnections
 	c := &http.Client{Transport: tr}
 	return NewVMStorage(*addr, *basicAuthUsername, *basicAuthPassword, *lookBack, c), nil
 }