diff --git a/db/seeds.rb b/db/seeds.rb
index 8496126b6..69e1cb4d4 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -146,33 +146,36 @@ unless Rails.env.test?
     child_organisation: managing_agent2,
   )
 
-  if (Rails.env.development? || Rails.env.review?) && User.count.zero?
-    User.create!(
+  if Rails.env.development? || Rails.env.review?
+    User.find_or_create_by!(
       name: "Provider",
       email: "provider@example.com",
-      password: "password",
       organisation: org,
       role: "data_provider",
-      confirmed_at: Time.zone.now,
-    )
+    ) do |user|
+      user.password = "password"
+      user.confirmed_at = Time.zone.now
+    end
 
-    User.create!(
+    User.find_or_create_by!(
       name: "Coordinator",
       email: "coordinator@example.com",
-      password: "password",
       organisation: org,
       role: "data_coordinator",
-      confirmed_at: Time.zone.now,
-    )
+    ) do |user|
+      user.password = "password"
+      user.confirmed_at = Time.zone.now
+    end
 
-    User.create!(
+    User.find_or_create_by!(
       name: "Support",
       email: "support@example.com",
-      password: "password",
       organisation: org,
       role: "support",
-      confirmed_at: Time.zone.now,
-    )
+    ) do |user|
+      user.password = "password"
+      user.confirmed_at = Time.zone.now
+    end
 
     pp "Seeded 3 dummy users"
   end
diff --git a/spec/db/seeds_spec.rb b/spec/db/seeds_spec.rb
new file mode 100644
index 000000000..15891b2da
--- /dev/null
+++ b/spec/db/seeds_spec.rb
@@ -0,0 +1,47 @@
+require "rails_helper"
+require "rake"
+
+RSpec.describe "seeding process", type: task do
+  # rubocop:disable RSpec/ExpectOutput
+  around do |example|
+    original_stdout = $stdout
+    $stdout = File.open(File::NULL, "w")
+
+    example.run
+
+    $stdout = original_stdout
+  end
+  # rubocop:enable RSpec/ExpectOutput
+
+  before do
+    Rake.application.rake_require("tasks/rent_ranges")
+    Rake::Task.define_task(:environment)
+
+    allow(Rails.env).to receive(:test?).and_return(false)
+    allow(Rails.env).to receive(:review?).and_return(true)
+  end
+
+  it "sets up correct data" do
+    expect {
+      Rails.application.load_seed
+    }.to change(User, :count).by(7)
+     .and change(Organisation, :count).by(8)
+     .and change(OrganisationRelationship, :count).by(4)
+     .and change(Scheme, :count).by(3)
+     .and change(Location, :count).by(3)
+     .and change(LaRentRange, :count).by(15_450)
+  end
+
+  it "is idempotent" do
+    Rails.application.load_seed
+
+    expect {
+      Rails.application.load_seed
+    }.to not_change(User, :count)
+     .and not_change(Organisation, :count)
+     .and not_change(OrganisationRelationship, :count)
+     .and not_change(Scheme, :count)
+     .and not_change(Location, :count)
+     .and not_change(LaRentRange, :count)
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 25429adc8..c5ea8e451 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -114,3 +114,5 @@ RSpec.configure do |config|
   config.before { RequestHelper.stub_http_requests }
   config.after { RequestHelper.real_http_requests }
 end
+
+RSpec::Matchers.define_negated_matcher :not_change, :change