diff --git a/Cargo.lock b/Cargo.lock
index 1cb8811..02be16c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -30,6 +30,12 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "libc"
+version = "0.2.186"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.106"
@@ -160,6 +166,7 @@ name = "zfs_backup"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "libc",
  "serde",
  "toml",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index aed3913..46888ca 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,5 +5,6 @@ edition = "2024"
 
 [dependencies]
 anyhow = "1.0.98"
+libc = "0.2.186"
 serde = { version = "1.0", features = ["derive"] }
 toml = "0.9.2"
diff --git a/src/main.rs b/src/main.rs
index b534054..6c51fc9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,8 +1,8 @@
-use std::env;
 use std::io::stdin;
 
 use anyhow::{Context, Result, bail};
 
+use libc::geteuid;
 use zfs_backup::cmd::zfs::zpool_import;
 use zfs_backup::config;
 use zfs_backup::encryption;
@@ -119,8 +119,8 @@ fn ask_user_confirmation(todos: &Vec<todo::Todo>) -> Result<bool> {
 }
 
 fn verify_running_as_root() -> Result<()> {
-    let uid = env::var("USER")?;
-    if uid != "root" {
+    let uid = unsafe { geteuid() };
+    if uid != 0 {
         bail!("must be run as root")
     }
     Ok(())