Bathroom Renovation Hot Water Planning: What to Check Before Waterproofing and Tiling

May 26, 2026

A bathroom renovation is not just about tiles, vanities and tapware. Before the room is waterproofed and finished, it is worth checking whether the home’s hot water system, pipework, valves and fixture choices will still suit the new bathroom.

This matters because a renovated bathroom can change how the household uses hot water. A larger shower head, freestanding bath, twin shower, extra ensuite or higher-flow fixture can make an older hot water system feel undersized very quickly.

Hot Water Outlet sells supply-only hot water systems, including heat pump hot water systems, electric hot water systems, gas hot water systems, instant gas hot water systems, solar hot water systems and valves, pipework and fittings.

For bathroom renovation plumbing, rough-ins, toilet relocation, shower wastes, fixture fit-off, installation, repairs, servicing, gas fitting, electrical work or on-site plumbing advice, use a licensed trade such as JR Gas & Water through their bathroom renovation plumbing service or broader plumbing services across Greater Brisbane and the Gold Coast.

Quick answer

Before waterproofing and tiling a bathroom, homeowners should check whether the existing hot water system, pipework, valves, shower flow, bath size, toilet set-out, mixer locations and drainage layout suit the new design. Hot Water Outlet can help compare supply-only hot water systems and related products, but bathroom renovation plumbing, installation, gas work, electrical work and on-site service work should be handled by licensed trades.

Why hot water planning matters before the bathroom is finished

Once a bathroom is waterproofed and tiled, plumbing changes become harder, slower and more expensive.

That is why hot water and plumbing product choices should be considered early, especially if the renovation includes:

A larger shower head
Twin showers
A freestanding bath
A new ensuite
More bathrooms being used at once
A move from bath/shower combo to walk-in shower
A change from standard shower to rainfall shower
New tapware or wall mixers
New valves or pipework
A hot water system that is old or unreliable
A change from electric to heat pump or gas hot water
A move from storage to instant gas hot water

Hot Water Outlet is useful for supply-only product comparison. The licensed plumber still needs to confirm whether the selected product suits the home, the bathroom layout, available services and installation requirements.

When Hot Water Outlet can help

Hot Water Outlet is best suited to supply-only product comparison before or during a bathroom renovation.

This may include:

Replacing an old hot water system before the new bathroom is finished
Comparing electric, heat pump, gas, instant gas and solar hot water systems
Checking whether the current system can support a larger shower or bath
Comparing replacement options before the plumber finalises the rough-in
Reviewing valves, pipework and fittings that may be needed by licensed trades
Planning product choices before tiles, waterproofing and cabinetry are locked in

Hot Water Outlet can help you compare supply-only:

Hot Water Outlet sells supply-only products and may help organise quotes from reputable installers where appropriate. It should not be treated as a bathroom renovation plumbing, installation, repair or on-site service business.

When JR Gas & Water is the better next step

Bathroom renovation plumbing should be handled by licensed trades.

Use JR Gas & Water for:

Bathroom renovation plumbing
Plumbing services across Greater Brisbane and the Gold Coast
Bathroom rough-ins
Toilet relocation
Shower waste and floor waste planning
Vanity water and waste connections
Fixture fit-off
Drainage alterations
Pipework replacement
Leak detection
Hot water installation or repairs
Gas fitting where gas work is involved
On-site plumbing advice before waterproofing and tiling

Hot Water Outlet can help with product selection. JR Gas & Water can help when the renovation needs licensed plumbing, installation, drainage, gas fitting, repairs or site assessment.

Check your hot water system before renovating

A new bathroom can quickly expose an old hot water problem.

You should review your existing hot water system if:

It already runs out of hot water
Recovery time is slow
The system is old or unreliable
The renovation includes a larger shower head
A freestanding bath is being added
Twin showers are planned
The household has grown
More bathrooms will be used at once
The existing system is leaking or rusty
You want to compare lower running cost options
The current system location clashes with renovation plans

A bathroom renovation is often a good time to compare supply-only hot water systems, especially if the current system is close to replacement age or no longer suits the household.

The right system depends on the home, not just the bathroom. Household size, available space, power supply, gas availability, hot water demand, installation location and site conditions all matter.

Comparing hot water options before a bathroom renovation

Heat pump hot water

A heat pump can reduce running costs compared with standard electric storage when selected and installed correctly. It can suit many homes where there is suitable outdoor space, airflow, drainage and household demand.

Compare supply-only heat pump hot water systems if the renovation is part of a broader move away from standard electric storage.

Heat pumps need careful placement. Noise location, airflow, access, drainage and outdoor space should be checked by a licensed installer before the system is chosen.

Electric hot water

Electric storage remains a familiar option for many homes, especially where the existing setup is simple and the household wants a straightforward replacement type.

Compare supply-only electric hot water systems if the current system is electric and the home suits a like-for-like storage replacement.

Electrical work should always be completed by a licensed electrician.

Gas hot water

Gas hot water may suit homes with suitable gas supply and existing gas infrastructure.

Compare supply-only gas hot water systems if the home already uses gas and the site suits a gas storage option.

Gas work should always be completed by a licensed gas fitter.

Instant gas hot water

Instant gas hot water can suit homes wanting continuous flow hot water, but gas supply, sizing, flow rates and installation conditions matter.

Compare supply-only instant gas hot water systems if the renovation includes higher hot water demand or a shift away from storage.

Instant gas systems need to be sized and installed correctly. The number of bathrooms, simultaneous use, gas supply and water demand all matter.

Solar hot water

Solar hot water can suit selected homes with the right roof, orientation, household demand and installation conditions.

Compare supply-only solar hot water systems if you are replacing an existing solar setup or comparing solar against heat pump, electric or gas options.

Roof work, plumbing and electrical work should always be handled by the correct licensed trades.

Shower upgrades can increase hot water demand

A new shower can use more hot water than the old one, especially if the bathroom renovation includes a more open, comfortable layout.

Hot water demand may increase with:

Larger shower heads
Rainfall showers
Twin showers
Longer shower times
Higher-flow fixtures
Multiple bathrooms being used at once
More people using the bathroom daily

This does not mean every bathroom renovation needs a new hot water system. It does mean the existing system should be checked before the bathroom is finished.

If the current system is already struggling, compare supply-only hot water systems before tiles and final fit-off are complete.

Bath additions need hot water planning

A freestanding bath or larger bath can look great in a renovation, but it can also place more demand on the hot water system.

Before choosing a bath, consider:

Bath capacity
Existing storage tank size
Hot water recovery time
Number of people in the home
Whether showers and the bath may be used at the same time
Whether the bath will be used often
Whether the existing hot water system is old
Whether the bathroom is part of a larger renovation

A bath is not only a design decision. It can change the practical hot water needs of the home.

If the home currently has a small or ageing storage system, it may be worth comparing electric, heat pump, gas or instant gas replacement options before the bathroom layout is finalised.

Valves, pipework and fittings should not be an afterthought

Bathroom renovations often involve new mixers, valves, isolation points, flexi hoses, wastes, fittings and pipework changes.

Hot Water Outlet stocks supply-only valves, pipework and fittings, but these products need to be selected and installed correctly.

Do not modify:

Pressure limiting valves
Tempering valves
Relief valves
Gas fittings
Hot water pipework
Cold water pipework
Waste pipework
Electrical connections
Shower or bath plumbing

Incorrect parts or poor installation can create pressure, safety, performance and compliance problems.

A licensed plumber should confirm which valves, fittings and pipework are required for the renovation.

Product choices to confirm before rough-in

Before the plumber completes the rough-in, confirm the products and fixture choices that affect plumbing set-out.

These may include:

Toilet type and set-out
Vanity type and drawer layout
Basin type
Basin mixer or wall mixer
Shower mixer
Shower outlet
Shower head style
Bath type
Bath spout location
Floor waste and grate style
Hot water system plans
Any valve or fitting requirements
Whether the current hot water system is being replaced
Whether the new bathroom will increase hot water demand

Hot Water Outlet is most relevant for hot water systems and related supply-only parts. For toilet relocation, shower waste planning, vanity plumbing, drainage and rough-in work, use a licensed plumber.

Renovation plumbing should be planned before waterproofing

Waterproofing and tiling should only happen once the plumbing layout is correct.

A licensed plumber should confirm:

Toilet set-out
Shower waste location
Floor waste location
Vanity water and waste positions
Bath water and waste positions
Mixer depth
Pipe condition
Water pressure
Drainage fall
Hot water supply
Tempering requirements where applicable
Testing before close-up
Access for future servicing

JR Gas & Water’s bathroom renovation plumbing service is the correct pathway for bathroom rough-in, drainage changes, fixture fit-off and renovation plumbing support.

Common hot water planning mistakes in bathroom renovations

Avoid these common mistakes:

Choosing a large shower without checking hot water capacity
Adding a bath without checking storage or recovery
Buying fixtures before confirming pipe locations
Choosing a heat pump without checking outdoor space and airflow
Choosing instant gas without checking gas supply and flow demand
Leaving an old unreliable hot water system until after the bathroom is finished
Forgetting tempering requirements
Assuming all replacement systems suit the same location
Ignoring access for future servicing
Treating product supply and licensed installation as the same thing
Ordering valves or fittings without plumber confirmation

Good planning separates product selection from site work. The product still needs to suit the home, and the licensed trades still need to confirm what can be installed safely and correctly.

Older Brisbane homes and bathroom renovations

Older Brisbane homes can hide hot water and plumbing issues that only become obvious during renovation.

Common issues include:

Older electric storage systems
Ageing copper or galvanised pipework
Low or inconsistent water pressure
Previous renovation changes
Narrow side access
Clay soil and drainage movement
Established trees affecting drains
High-set homes with long pipe runs
Mixed old and new plumbing
Hot water systems near the end of their service life

If the home has an old hot water system, the renovation is a sensible time to compare supply-only electric hot water, heat pump hot water, gas hot water or instant gas hot water options.

For the plumbing work itself, use JR Gas & Water’s plumbing services across Greater Brisbane and the Gold Coast.

Gold Coast bathroom renovation considerations

Gold Coast homes can bring different bathroom renovation conditions.

Common considerations include:

Coastal corrosion
Outdoor hot water system exposure
Duplex and townhouse access
Flat blocks with drainage constraints
Slab construction
Body corporate requirements
Tight side access
Limited outdoor space
Heat pump noise and airflow placement
Gas availability
Shared services in some properties

For supply-only product comparison, Hot Water Outlet can help homeowners review hot water system options. For bathroom plumbing, installation, access, drainage, gas fitting or repair work, use licensed trades.

Slab homes, townhouses and units

Bathroom renovations in slab homes, townhouses and units need careful planning before products are ordered.

Ask these questions early:

Can the toilet waste move?
Can the shower waste move?
Will concrete cutting be required?
Is the bathroom upstairs?
Are there rooms or units below?
Are services shared?
Does body corporate approval apply?
Will a new hot water system fit in the current location?
Is there outdoor space and airflow for a heat pump?
Is there suitable gas supply for instant gas?
Will the selected system be serviceable later?

Hot Water Outlet can help compare supply-only systems, but the plumber and installer need to confirm whether the site can support the selected product and layout.

Renovation timing: when to compare hot water products

The best time to compare hot water products is before the rough-in is finalised.

Compare early if:

The old system is unreliable
The bathroom layout is changing
Hot water demand is increasing
A bath is being added
A second bathroom or ensuite is being built
The homeowner wants a heat pump
Gas and electric options are being compared
The outdoor unit location may change
The current system is leaking or corroded
Valves or pipework may need updating

Leaving hot water decisions until after tiling can make the project harder, especially if pipework, valves, gas supply, electrical supply or outdoor placement need to change.

What homeowners can safely plan themselves

Homeowners can prepare useful information before speaking with trades.

Helpful details include:

Existing hot water system type
Photos of the hot water system label
Number of bathrooms
Number of people in the home
Preferred shower type
Whether a bath is being added
Whether the existing system runs out
Whether the home uses gas
Whether solar PV is installed
Whether the system is indoor or outdoor
Photos of the bathroom and existing hot water system
Any body corporate or access restrictions
Any known leaks, rust or hot water issues

Do not move pipework, alter drains, modify valves, adjust gas components, open electrical equipment or attempt plumbing work yourself.

What needs a licensed trade

Use licensed trades for:

Bathroom renovation plumbing
Rough-in plumbing
Fixture fit-off
Toilet relocation
Shower waste installation
Floor waste planning
Drainage changes
Pipework alterations
Valve installation
Hot water installation
Hot water repairs
Gas fitting
Electrical work
Leak detection
Final connection and testing

Gas work should always be completed by a licensed gas fitter. Electrical work should always be completed by a licensed electrician. Plumbing work should be completed by a licensed plumber.

Hot Water Outlet can help compare supply-only products. The site work should be handled by the correct licensed trade.

FAQs

Can Hot Water Outlet help with a bathroom renovation?

Hot Water Outlet can help with supply-only hot water system and related product comparison before or during a bathroom renovation. Bathroom renovation plumbing, installation, gas work, electrical work, drainage and fixture fit-off should be handled by licensed trades.

Should I replace my hot water system during a bathroom renovation?

It may be worth considering if the current system is old, leaking, rusty, unreliable or already running out of hot water. A new bathroom with a larger shower, bath or extra ensuite can increase hot water demand.

What hot water system is best for a bathroom renovation?

There is no single best option for every home. Heat pump, electric, gas, instant gas and solar hot water systems all suit different situations. The right choice depends on household size, available space, energy supply, gas availability, usage patterns and installation requirements.

Can a new shower reduce hot water performance?

A new shower can make hot water issues more obvious if it has a higher flow rate or if more bathrooms are used at once. If the existing system is already struggling, compare replacement options before the bathroom is complete.

Can I replace electric hot water with a heat pump during a renovation?

You may be able to, but suitability depends on outdoor space, airflow, drainage, household demand, noise location, electrical requirements and installation conditions. Compare heat pump systems early and get licensed site advice before ordering.

Can I change from storage hot water to instant gas?

It may be possible if the home has suitable gas supply, pipe sizing, flow demand and installation conditions. Instant gas hot water should be sized and installed by licensed trades.

Does Hot Water Outlet install bathroom plumbing?

No. Hot Water Outlet sells supply-only hot water systems and related products. For bathroom renovation plumbing, rough-ins, fixture fit-off, gas fitting, drainage, installation or repairs, use licensed trades such as JR Gas & Water.

Should I order a hot water system before the plumber checks the site?

It is better to have the site checked before ordering if you are changing system type, moving the unit, adding a bath, increasing shower demand or switching between electric, gas, heat pump or solar. This helps reduce the risk of choosing a product that does not suit the home.

Planning a bathroom renovation?

Before waterproofing and tiles go in, make sure the hot water system and product choices line up with the new bathroom.

Hot Water Outlet can help you compare supply-only hot water systems, heat pump hot water systems, electric hot water systems, gas hot water systems, instant gas hot water systems, solar hot water systems and valves, pipework and fittings.

For bathroom renovation plumbing, rough-ins, fixture fit-off, drainage changes, hot water installation, leak repairs, gas fitting or on-site plumbing support, book JR Gas & Water through the bathroom renovation plumbing page or the quote request and bookings page.

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