Water Treatment in a Building: Point of Entry or Point of Use

Hard water damages equipment, and taste complaints are a different problem again. Comparing whole building treatment with treatment at the tap.

Treating water at the point of entry protects everything downstream: pipework, water heaters, cooling equipment, washing machines and sanitary fittings. Treating at the point of use protects only the tap it serves but delivers a much higher quality where it matters for drinking. The two solve different problems, and buying one while describing the other is the most common source of disappointment.

Point of entry treatment at a glance

Equipment installed where the supply enters the property, typically sediment filtration followed by softening or scale control, sometimes with disinfection where storage tanks are involved. It protects the whole installation, reduces scale in heaters and appliances, and improves the performance of anything that boils or heats water. It consumes salt or media, requires drainage for backwashing, and needs a servicing routine to stay effective.

Point of use treatment at a glance

A smaller unit installed under a sink or on a dedicated tap, typically combining fine filtration with a membrane stage and a post filter. It addresses taste, odour and dissolved contaminants at the drinking point to a standard a whole building system would be uneconomic to reach. It wastes some water to drain depending on the technology, and it protects nothing beyond the outlet it serves.

What it protects

Point of entry treatment: The whole installation, including heaters, appliances and pipework.

Point of use treatment: Only the outlet it serves, at a higher standard of treatment.

Installation requirements

Point of entry treatment: Plant space, drainage for backwash or regeneration, and a bypass for servicing.

Point of use treatment: Space in a cupboard, a drain connection and a dedicated tap.

Running cost

Point of entry treatment: Salt or media replacement, periodic servicing and water used during regeneration.

Point of use treatment: Cartridge and membrane replacement on a schedule, plus water sent to drain.

Effect on taste and dissolved content

Point of entry treatment: Limited, since softening exchanges minerals rather than removing dissolved solids.

Point of use treatment: Substantial, which is why drinking water complaints are solved here.

Consequence of neglected servicing

Point of entry treatment: Scale protection stops, and in some configurations water quality worsens.

Point of use treatment: Filter performance declines and the unit can become a contamination point itself.

Suitability for a tenanted building

Point of entry treatment: Landlord responsibility, maintained centrally and funded through the service charge.

Point of use treatment: Tenant responsibility, with no coordination needed from the owner.

When point of entry treatment wins

• Properties with significant scale deposition damaging heaters and fittings.
• Buildings where tank storage means water quality must be managed across the whole system.
• Owners protecting expensive equipment such as boilers, chillers or laundry plant.
• Villas where every outlet should deliver the same treated water quality.

When point of use treatment wins

• Drinking water quality in a kitchen or a staff area.
• Rented premises where installing whole building plant is not permitted.
• Apartments where the supply is shared and the resident controls only their own unit.
• Specific requirements such as a clinic treatment room or a laboratory supply.

How to decide

Test the supply before deciding anything. If the issue is scale damaging equipment, the answer is at the point of entry and the business case is equipment life. If the issue is taste, odour or drinking quality, the answer is at the point of use and whole building treatment will not deliver it economically. Many properties need both: entry treatment to protect the installation, and a drinking water unit in the kitchen. Where water is stored in tanks, the storage and its cleaning regime usually matter more than any filter.

Get a water analysis from an accredited laboratory covering hardness, total dissolved solids, chloride and microbiological indicators, taken from the actual outlet rather than from the street. Ask any supplier to state which parameter in that report their equipment changes and by how much. Request the servicing schedule and consumable cost over five years. For storage tanks, agree a cleaning and inspection frequency, because a treated supply entering a neglected tank arrives at the tap in the condition of the tank. Drinking water quality requirements are set by the relevant authorities and are reviewed periodically, so confirm the current standard that applies to your building type.

Domira works on buildings that already exist: surveying what is installed, specifying the systems that have to be replaced, and running maintenance and refurbishment work around the people using the property. Tell Domira which asset you are responsible for and we will say what we would inspect first.