Why Your Windows Streak — Water-Fed Pole and Deionised-Water Cleaning in Adelaide, Explained

Streaks happen because tap water carries dissolved minerals — calcium, magnesium, silica — that dry on the glass as a haze the moment the water evaporates. Deionised water has those minerals stripped out at the resin tank, so it dries clean and leaves nothing behind. A water-fed pole delivers that deionised water through a carbon-fibre pole to a brush head at the glass, which means the crew works from the ground instead of a ladder, on a working-at-heights regime that’s safer, faster, and far less likely to drop a ladder leg through a heritage gutter. That is the practical answer to “why do my windows streak after I clean them” — and it is the reason every reputable Adelaide cleaning operator has put the squeegee away on two-storey exterior work and switched to pure water at the brush.

This article is the plain-English explainer. It covers what’s actually in Adelaide tap water, how a deionising tank produces water clean enough to leave a spotless dry, how the water-fed pole replaces the ladder for almost every two-storey job, and where the traditional squeegee + microfibre method still earns its keep on interior and ground-floor work.

The mineral problem — what’s actually in Adelaide tap water

Adelaide’s mains water is moderately hard by Australian standards. SA Water publishes a typical water analysis for each metropolitan supply zone, and the readings most relevant to window cleaning sit in three categories: total dissolved solids (TDS), total hardness (calcium and magnesium expressed as calcium carbonate), and silica.

Across most metropolitan Adelaide zones the readings sit in these ranges:

• Total dissolved solids (TDS): roughly 200 to 700 mg/L depending on the season and the source mix (Murray-river-pumped vs reservoir-sourced)
• Total hardness: roughly 100 to 220 mg/L as CaCO3 — moderately hard, with seasonal variation
• Silica: present at low concentrations but enough to drive the haze that does not dissolve back off in a re-wash

Reservoir-and-Murray-blend water is the Adelaide story. The mineral profile is fine for drinking, fine for cooking, fine for showering — and a streak factory on a window pane that’s still hot at 4pm in summer.

When tap water is sprayed onto a window and then dries, the water evaporates and the minerals don’t. They stay on the glass as a microscopic deposit. On a single wash you might not see it; on a sixth wash on the same pane in the same year, the layered deposit catches light at a raking angle and looks like the cleaner did a poor job. The cleaner did a fine job — the water lost the argument.

Hot weather makes it worse. Evaporation accelerates, the water dries before the crew can rinse it down, and the mineral deposit sets harder. A 38°C summer afternoon in a west-facing aspect is the worst-case combination of inputs. (For the chemistry of severe deposit cases — sprinkler overspray, evaporative-cooler runoff, builders’ splatter — see the sister article on hard-water staining and mineral etch on Adelaide windows.)

How deionised water solves it

Deionised water — sometimes called “pure water” or “DI water” — is tap water that has had the dissolved ions stripped out. The chemistry is straightforward: tap water passes through an ion-exchange resin tank where positive ions (calcium, magnesium, sodium) are swapped for hydrogen, and negative ions (chloride, sulphate, bicarbonate, silica) are swapped for hydroxyl. The hydrogen and hydroxyl recombine into water. The minerals stay locked in the resin until the resin is regenerated.

The output is water with a measured conductivity — the standard at the brush head should read under 5 microsiemens per centimetre (µS/cm), and most professional rigs target under 1 µS/cm. Tap water in Adelaide reads in the hundreds of µS/cm for comparison. That conductivity reading is what every reputable operator checks before they start a job — a calibrated TDS meter at the nozzle is the gear-check equivalent of a tradesman testing a circuit before they touch it.

Three points worth being clear on:

• “Filtered water” is not deionised water. A carbon filter strips chlorine and some organics; it does not strip the calcium and silica that drive the streak. A consumer-grade jug filter is irrelevant to this problem.
• Reverse-osmosis (RO) water is close, but not always enough. RO membranes reject 90 to 99 per cent of dissolved solids and produce excellent low-TDS water. Many professional rigs use RO as a pre-treatment to extend resin life, then polish through a DI tank to reach sub-1 µS/cm. RO alone, on Adelaide tap, leaves enough mineral residue to streak on hot work.
• DI resin exhausts. A resin tank treats a finite volume of water before the ion-exchange capacity is used up. The conductivity reading is the gauge — when it climbs above 5 µS/cm, the tank needs regeneration or replacement. Cheap operators run exhausted resin and don’t notice; the streaks land back on the customer’s pane.

The practical test for the homeowner: ask the cleaner for the conductivity reading at the brush head before the job starts. The number should be a single digit µS/cm. If they don’t carry a meter, they’re not running the gear they’re charging for.

The water-fed pole — what’s actually on the truck

A water-fed pole rig is four pieces of equipment working together:

1. A water source and pre-treatment loop. Tap water from the property’s mains tap is fed into a pre-filter (sediment), then either a reverse-osmosis membrane stack or directly into the DI tank, depending on the rig. High-volume residential rigs run RO + DI; smaller mobile rigs run DI-only with frequent resin regeneration.

2. A pump and pressurised hose. The treated water is pumped at low pressure through a flexible hose. The hose runs from the truck or a wheeled trolley to the base of the carbon-fibre pole.

3. The carbon-fibre telescopic pole. Most professional residential poles run 8 to 14 metres of working reach — enough for a typical two-storey gable or a third-storey commercial fascia from ground level. The pole is hollow; the water hose runs internally to the brush head. Carbon fibre is light enough that a single technician can work an extended pole at full reach without the elbow-and-shoulder fatigue an aluminium pole produces in twenty minutes.

4. The brush head. The brush at the top of the pole has a row of bristles (boar’s hair, nylon, or hybrid) plus a water-feed jet that delivers the deionised water at the glass. The crew agitates the pane with the brush — the bristles dislodge the dirt, the water lifts it off — and then rinses with a final pass of clean water before withdrawing the brush.

The technique is repeatable: scrub at the top, work down, scrub the corners, rinse top to bottom, withdraw clean. The water sheets off, dries by evaporation, and leaves nothing because there’s nothing in the water to leave. No detergent, no rinse-aid, no chamois finish, no microfibre touch-up. The dry is the finish.

Why the water-fed pole is the safer working-at-heights answer

Falls from height are the most common cause of fatal injury in Australian construction, trades, and cleaning industries. Safe Work Australia’s working-at-heights guidance is explicit: where work above ground level can be eliminated by working at ground level instead, that elimination is the highest control in the hierarchy. Where it can’t be eliminated, the next control is a passive fall-prevention system (guardrails, scaffolds, EWPs); after that, fall-arrest systems with engineered anchors; and at the bottom of the hierarchy, ladders.

Window cleaning has historically lived at the bottom of that hierarchy — extension ladder against a fascia, a one-handed reach over the gutter, balance-and-pray. The water-fed pole moves the work up to the top of the hierarchy: the elimination control. The crew never leaves the ground.

Under the Work Health and Safety Act 2012 (SA) and the equivalent regulations, a “person conducting a business or undertaking” (PCBU) must so far as is reasonably practicable eliminate or minimise risks to workers and to others affected by the work. A residential cleaning crew working a ladder on a heritage roof edge with a brittle 1920s gutter, a fragile tile field, and a public footpath underneath fails the reasonable-practicability test the moment a ground-level alternative — the water-fed pole — exists for the same job. Most reputable Adelaide operators have done that maths and switched. Those who haven’t are running uninsured exposure on every two-storey job.

The practical safety wins at the property level:

• No ladder above 3 metres on the heritage gutter that bends if a 90 kg crew member leans on it
• No harness anchor on a roof with no engineered anchor point — most pre-1990 Adelaide roofs don’t have one
• No public-footpath risk from a falling extension ladder or dropped squeegee
• Faster crew time on the same job — typical two-storey home is 30 to 60 minutes faster on a water-fed pole than on a ladder
• Lower public liability premiums for the operator — and that saving lands in the residential rate

The Window and Façade Association of Australia and New Zealand (WFAANZ) tracks the same shift in commercial work — water-fed pole and rope-access have replaced ladder work on most commercial frequencies in metro Australia in the past decade. Vista Fox runs the same gear on residential because the safety logic and the finish quality both win.

Where the squeegee + microfibre still earns its keep

The water-fed pole is not a universal answer. Traditional squeegee-and-microfibre — the technique most homeowners associate with “real” window cleaning — is still the right tool in defined cases:

• Interior windows. Pure-water poles are an exterior tool. Inside, the crew runs squeegee + microfibre with a low-residue cleaning solution, taping protective drop sheets where needed. Indoor work is also where the crew has the time and angle to detail the corners and the frame.
• Ground-floor commercial close-up work. Shopfront glass at street level — a one-storey retail frontage where the crew is operating at arm’s length — is faster on a hand-held squeegee than on a pole. The crew swaps gear by location.
• Leadlight and decorative panels. A water-fed pole bristle agitating against a leaded came joint can stress the soft-metal seam over time; on heritage leadlight the right tool is a hand-detail with low pressure, soft cloths, and a careful rinse — not a pressurised pole. (For why heritage leadlight needs UV protection in addition to careful cleaning, see leadlight UV protection film in Adelaide — a related architectural-film conversation that touches the same heritage-glass stock.)
• Edge-stained heritage frames. Hand-detail handles a delicate frame that mechanical agitation might lift paint from.
• Internal partition glass and shop-front interiors. Standard squeegee work, often with specialist cleaners for branded printed glass.

The fastest summary: exterior + above-ground = water-fed pole; interior + close-up + delicate = squeegee and microfibre. A reputable crew runs both and chooses by surface.

Why your DIY squeegee streaks — the four common failures

Most homeowners have tried the DIY squeegee at least once and found it streakier than the cleaner did. The reason is almost always one of four:

1. Tap-water minerals. The DIY job uses tap water + a splash of dishwashing liquid. The dishwashing liquid raises a foam that lifts the dirt; the rinse leaves a mineral haze. The deionised water step doesn’t exist. Streaks land.

2. Wrong squeegee angle. A squeegee held at 90 degrees to the glass scrapes water rather than channelling it. The professional angle is around 30 degrees, with the trailing edge of the rubber doing the work. A homeowner squeegee passes that haven’t got the angle right leave a row of micro-bands.

3. A dirty squeegee rubber. Professional squeegee rubbers are wiped clean every pass — a folded clean cloth in the off-hand, a wipe between strokes. A DIY squeegee picks up soap and grit on stroke one and lays it back on the glass for stroke two through stroke ten. The streak source is on the tool.

4. Finishing with a dirty cloth. The detail at the end — the corner wipe, the bottom edge dry — is where most DIY jobs land their final visible streak. A laundered tea-towel or a microfibre cloth that has lived in the cleaning bucket is not clean enough. Professional finishers carry fresh microfibre per pane on detail-grade work.

Each of those four is fixable with technique. The DIY job that fails them isn’t badly done by a careless owner — it’s badly tooled. The professional kit (deionised water, professional squeegee, fresh cloths, the angle) is what the rate-card pays for.

When to call us

The cases where water-fed pole + DI is the right answer:

• Two-storey or above-ground exterior work. The default. Faster, safer, cleaner finish than a ladder job.
• Heritage homes with no engineered roof anchor. Most pre-1990 Adelaide roofs. The water-fed pole is the only correct working-at-heights answer.
• Coastal homes with salt-spray-loaded glass — Henley, Glenelg, West Beach, Brighton. The salt deposit dissolves into the deionised water and rinses clean; tap water just smears it.
• Recurring residential schedules (quarterly or six-monthly) where the streak-free finish needs to hold through to the next visit.
• Pre-photo and pre-sale jobs (cross-link real-estate pre-sale window prep in Adelaide) where the open-inspection photo cannot have a single visible streak in the front-of-house glass.
• Commercial frequencies — retail, body-corp, school and clinic — where ladder work fails the modern PCBU duty-of-care test.

The cases where the answer is squeegee-and-microfibre or a hybrid: interior work, ground-floor retail, heritage leadlight, decorative panels.

Residential window cleaning and commercial window cleaning both run on the same water-fed pole + DI rig. The pricing context — what a deionised-water clean actually costs in 2026 — sits inside the window cleaning cost in Adelaide guide.

Frequently asked questions

Why do my windows streak after I clean them?

Tap water leaves a mineral residue when it dries. Calcium, magnesium and silica from Adelaide’s reservoir-and-Murray-blend water settle on the glass and catch light at raking angles. Deionised water has those minerals removed at the resin tank, so there is nothing left to dry on the pane. Streaks are a water problem first and a technique problem second.

What is deionised water and how is it made?

Deionised water is water that has been passed through an ion-exchange resin to strip out dissolved minerals. Tap water enters a resin tank; the resin swaps the calcium, magnesium, sodium, silica and bicarbonate ions for hydrogen and hydroxyl, which recombine into pure water. The output is checked at the brush head with a TDS or conductivity meter and should read under 5 microsiemens per centimetre. Most professional rigs combine reverse-osmosis pre-treatment with a DI polishing tank.

Is water-fed pole cleaning better than squeegee?

For exterior and above-ground work, yes — the deionised water sheets off the pane, dries clean without any mineral residue, and the crew works safely from the ground rather than balancing on a ladder against a fragile heritage gutter. For interior windows, ground-floor retail glass, and delicate heritage leadlight, the right answer is still a hand-detailed squeegee with microfibre finishing. A reputable crew carries both gear sets and chooses by surface.

Will it work on my second-storey windows?

Yes — that is the case the water-fed pole is built for. Most professional residential poles reach 8 to 14 metres from ground level, which covers any standard two-storey Adelaide home, most three-storey commercial frontages, and any second-storey gable on a heritage two-storey villa or townhouse. The reach is what makes it the safer answer compared to an extension ladder against a roof edge.

Does deionised water damage anything?

No. Deionised water is purer than rainwater and contains nothing that can react with glass, paint, render, leadlight came, or planting. It is safer for the building fabric and for the garden than the soap-and-rinse method, which leaves detergent residue on the render below the windows. The only material that can be affected by repeated deionised water exposure is bare metal not protected by paint or anodising — uncommon on a residential building, and not present on standard glass-and-frame assemblies.

Sources

• SA Water — Typical water analysis
• Safe Work Australia — Falls from heights guidance
• Government of South Australia — Work Health and Safety Act 2012 (SA)
• WFAANZ — Window and Façade Association of Australia and New Zealand