diff --git a/Modules/Core/Common/include/itkDomainThreader.h b/Modules/Core/Common/include/itkDomainThreader.h
index 07b06955439..7247b4fd049 100644
--- a/Modules/Core/Common/include/itkDomainThreader.h
+++ b/Modules/Core/Common/include/itkDomainThreader.h
@@ -104,11 +104,8 @@ class ITK_TEMPLATE_EXPORT DomainThreader: public Object
    * \warning When setting the desired number of work units, it might be clamped by
    * itk::MultiThreaderBase::GetGlobalMaximumNumberOfThreads().
    * */
-  ThreadIdType GetNumberOfWorkUnits() const
-  {
-    return this->m_MultiThreader->GetNumberOfWorkUnits();
-  }
-  void SetNumberOfWorkUnits( const ThreadIdType workUnits );
+  itkSetClampMacro(NumberOfWorkUnits, ThreadIdType, 1, ITK_MAX_THREADS);
+  itkGetConstMacro(NumberOfWorkUnits, ThreadIdType);
 
   /** Convenience methods to set/get the maximum number of threads to use.
    * \warning When setting the maximum number of threads, it will be clamped by
@@ -172,6 +169,7 @@ class ITK_TEMPLATE_EXPORT DomainThreader: public Object
    * well into that number.
    * This value is determined at the beginning of \c Execute(). */
   ThreadIdType                             m_NumberOfWorkUnitsUsed;
+  ThreadIdType                             m_NumberOfWorkUnits;
   typename DomainPartitionerType::Pointer  m_DomainPartitioner;
   DomainType                               m_CompleteDomain;
   MultiThreaderBase::Pointer               m_MultiThreader;
diff --git a/Modules/Core/Common/include/itkDomainThreader.hxx b/Modules/Core/Common/include/itkDomainThreader.hxx
index a0d44311a86..a0bd8e55062 100644
--- a/Modules/Core/Common/include/itkDomainThreader.hxx
+++ b/Modules/Core/Common/include/itkDomainThreader.hxx
@@ -26,11 +26,12 @@ namespace itk
 template< typename TDomainPartitioner, typename TAssociate >
 DomainThreader< TDomainPartitioner, TAssociate >
 ::DomainThreader()
+  : m_Associate(nullptr),
+    m_NumberOfWorkUnitsUsed(0)
 {
   this->m_DomainPartitioner = DomainPartitionerType::New();
   this->m_MultiThreader = MultiThreaderBase::New();
-  this->m_NumberOfWorkUnitsUsed = 0;
-  this->m_Associate = nullptr;
+  this->m_NumberOfWorkUnits = this->m_MultiThreader->GetNumberOfWorkUnits();
 }
 
 template< typename TDomainPartitioner, typename TAssociate >
@@ -45,18 +46,6 @@ DomainThreader< TDomainPartitioner, TAssociate >
   return this->m_MultiThreader;
 }
 
-template< typename TDomainPartitioner, typename TAssociate >
-void
-DomainThreader< TDomainPartitioner, TAssociate >
-::SetNumberOfWorkUnits( const ThreadIdType workUnits )
-{
-  if( workUnits != this->GetNumberOfWorkUnits() )
-    {
-    this->m_MultiThreader->SetNumberOfWorkUnits( workUnits );
-    this->Modified();
-    };
-}
-
 template< typename TDomainPartitioner, typename TAssociate >
 void
 DomainThreader< TDomainPartitioner, TAssociate >
@@ -92,24 +81,18 @@ void
 DomainThreader< TDomainPartitioner, TAssociate >
 ::DetermineNumberOfWorkUnitsUsed()
 {
-  const ThreadIdType threaderNumberOfThreads = this->GetMultiThreader()->GetNumberOfWorkUnits();
+  ThreadIdType numberOfWorkUnits = this->GetNumberOfWorkUnits();
 
   // Attempt a single dummy partition, just to get the number of subdomains actually created
   DomainType subdomain;
   this->m_NumberOfWorkUnitsUsed = this->m_DomainPartitioner->PartitionDomain(0,
-                                            threaderNumberOfThreads,
+                                            numberOfWorkUnits,
                                             this->m_CompleteDomain,
                                             subdomain);
 
-  if( this->m_NumberOfWorkUnitsUsed < threaderNumberOfThreads )
-    {
-    // If PartitionDomain is only able to create a lesser number of subdomains,
-    // ensure that superfluous work units aren't created
-    // DomainThreader::SetMaximumNumberOfThreads *should* already have been called by this point,
-    // but it's not fatal if it somehow gets called later
-    this->GetMultiThreader()->SetNumberOfWorkUnits(this->m_NumberOfWorkUnitsUsed);
-    }
-  else if( this->m_NumberOfWorkUnitsUsed > threaderNumberOfThreads )
+  this->GetMultiThreader()->SetNumberOfWorkUnits(this->m_NumberOfWorkUnitsUsed);
+
+  if( this->m_NumberOfWorkUnitsUsed > numberOfWorkUnits )
     {
     itkExceptionMacro( "A subclass of ThreadedDomainPartitioner::PartitionDomain"
                       << "returned more subdomains than were requested" );