If you only care about what you drink and cook with, an under sink filter is enough. If chlorine in the shower, sediment or discoloured water bothers you at every tap, you want a whole house system. Many homes end up with a simple version of both.
The right answer depends on what is in your water, so start there.
What is in Central Coast water?
Central Coast Council’s published water quality information shows three things that shape the decision:
- The water is soft. Hardness averaged 53 mg/L against a guideline of 200 mg/L, so scale is not the problem here.
- It is chlorinated. Chlorine keeps the water safe in the pipes, and how strongly you taste it depends on how far you are from the treatment plant.
- It is fluoridated, in line with NSW Health recommendations.
Add the occasional run of discoloured water from iron and manganese in the mains, and that is the list most households are dealing with. Our post on whether Central Coast tap water is safe to drink has the full numbers.
Whole house vs under sink: side by side
| Under sink filter | Whole house filter | |
|---|---|---|
| Where it goes | In the cupboard under the kitchen sink | On the main water line, after the meter |
| Which taps are filtered | One, usually a dedicated drinking tap or the kitchen mixer | Every tap, shower and appliance |
| Typical filter type | Carbon, or reverse osmosis | Sediment stage plus carbon stages |
| Chlorine taste and smell | Yes, at that tap | Yes, through the whole house |
| Sediment and discolouration | Yes, at that tap | Yes, before it reaches any fixture |
| Fluoride and PFAS | Yes, with a reverse osmosis unit | Not with standard carbon cartridges |
| Space needed | Cupboard space under the sink | Wall space outside, near the meter |
| Suits renters and units | Often, with the owner’s approval | Rarely, needs access to the main line |
| Best for | Drinking and cooking water | Showers, laundry, appliances and every tap |
When is an under sink filter the right choice?
Choose under sink if:
- your main complaint is the taste of drinking water
- you want fluoride or PFAS reduced, which means reverse osmosis at the kitchen tap
- you live in a unit, townhouse or rental without access to the main line
- you want filtered water without changing anything else in the house
One thing to know about reverse osmosis: it filters slowly, so most units store filtered water in a small tank under the sink and send some water to waste as they work. They also take up more cupboard space than a carbon filter.
When is a whole house filter the right choice?
Choose whole house if:
- you can smell chlorine in the shower
- you get discoloured water or sediment often enough to stain washing
- you want filtered water running through your hot water system, washing machine and dishwasher too
- you own the home and plan to stay
A whole house system must be sized for the home. One that is too small for the number of bathrooms can leave you with low water pressure, which is why it pays to have it specified and installed properly.
Can you have both?
Yes, and for some homes it is the best setup. A whole house carbon system does not remove fluoride. An under sink reverse osmosis unit does not help your shower.
If you want both, fit a whole house sediment and carbon system for the home, plus a reverse osmosis unit at the kitchen sink for drinking water. Each one does the job it is good at.
Do you need a water softener on the Central Coast?
No, not on town water. Softeners are for hard water, and Council’s supply is soft. If you are being quoted for a softener on a town water property here, get a second opinion.
What about homes on tank water?
If your home runs on a rainwater tank, the priorities change. There is no chlorine or fluoride to remove, but there can be sediment, leaf matter and bacteria. Tank systems are usually built around sediment filtration and UV treatment, not just carbon.
If your tank can be topped up from mains, Council requires backflow prevention so tank water cannot flow back into the drinking supply.
How much maintenance does a water filter need?
Every filter needs its cartridges changed on the manufacturer’s schedule. Council’s advice is blunt: filters that are not maintained can grow bacteria and make your water worse.
Before you choose a system, ask:
- How often do the cartridges need changing?
- Can I buy replacement cartridges locally?
- Can I change them myself, or does it need a service visit?
- Is there a bypass, so the house still has water while the system is being serviced?
If you would rather not track it yourself, we offer scheduled filter cartridge replacement and system maintenance as part of our water filtration systems service. It also slots in neatly with your regular plumbing maintenance.
Who should install a water filter?
A whole house filter is cut into your main water line, so it is a job for a licensed plumber. Under sink systems also connect to your water supply, and a leaking fitting inside a kitchen cupboard can do a lot of damage before anyone notices.
We install under sink carbon filters, whole house multi-stage systems, reverse osmosis units and UV purification across the Central Coast. We start with what is in your water and how your household uses it, and we will tell you if the simpler option will do the job.
Quick answers
Is a whole house water filter worth it? It is if your issue is at every tap, such as chlorine in the shower or regular discoloured water. For drinking water alone, an under sink filter does the job.
Does a whole house filter remove fluoride? Not with standard carbon cartridges. Reverse osmosis removes fluoride, and it is normally fitted under the kitchen sink.
Will a whole house filter reduce my water pressure? A correctly sized system should not cause a noticeable drop. An undersized one, or clogged cartridges, will.
Do I need a water softener on the Central Coast? No. Central Coast town water is soft.
Want a straight answer on which one suits your place? See our water filtration systems service, call 0414 259 179 or talk to Miracle Plumbing.
