On Monday, 7 September 2026, the head of Bekasi City's disaster agency (BPBD), Wiratma, told reporters what many parents had been waiting to hear: conditions were “much lighter than yesterday.” He was talking about volcanic ash from Anak Krakatau. The volcano began erupting on the night of Friday, 4 September, and Indonesia's weather agency BMKG tracked the ash moving toward Jakarta, Banten and West Java.
The city moved fast. The Environment Agency's monitoring station logged air quality as moderate at 10:00 on Sunday and good by 06:00 on Monday. BPBD set aside 1,000 masks for every district. The Education Office issued Circular No. 400.3/6/DISDIK.Set, moving all primary and junior high schools to remote learning on 8 and 9 September. On Thursday, 10 September, classes were back in person. “Looks like it's clear. Tomorrow as usual,” Mayor Tri Adhianto said.
Air can recover in two days. Ash that has already landed stays put. Some of it can sit on roof tiles and in gutters, or get pulled into the fins of an air conditioner's outdoor unit. On a two-storey house, those spots are the highest parts of the building and the ones owners check least.
Why You Shouldn't Hose Ash Into the Drain
Most people's first instinct is to grab a hose and spray the terrace clean. That is the one thing to avoid. Guidance from the United States Geological Survey (USGS), quoted by Metro TV on 8 September, explains that volcanic ash builds up quickly in drainage lines and can set like cement once it gets wet.
So flip the order. Dampen the floor or yard just enough to keep the ash from lifting, then shovel it into bags. Don't let it run into the street drain. A blocked drain in front of one house rarely stays one household's problem, because the channel runs past the neighbours on both sides.
What to Check on a Two-Storey House
Gutters and downpipes
USGS lists gutters among the parts of a building most vulnerable to ashfall, and says trouble can start with just a few millimetres of ash. It recommends two things: clean gutters as soon as it is safe, to prevent blockages and corrosion, and disconnect downpipes from the gutter while you clean so the ash doesn't go down into the drainage.
Timing matters. This dry season has run long, and since June BMKG has projected that El Niño will last into early 2027. Dry ash can sit in a gutter for weeks without being visible from the ground. The trouble shows up with the first heavy rain, when that ash turns to sludge and goes down the downpipe all at once. We covered routine gutter cleaning for leaves and dirt in our guide to gutter care on a two-storey house in the dry season. The difference with ash is that you don't flush it out with water.
The AC outdoor unit
An outdoor unit pulls in surrounding air to dump heat, and ash comes in with it. For condensers, USGS suggests vacuuming the ash off or blowing it away gently at low pressure, then wiping down. Wet cleaning isn't recommended at this stage. Indoor filters also need checking more often over the next few months, because fine particles keep getting drawn in. If your outdoor unit is bolted to a second-floor wall with nowhere to stand, leave it to a technician. For choosing and maintaining AC on a two-storey home, see our two-storey AC guide.
Water tanks and rainwater storage
A rooftop tank with a tight lid is generally fine. Check the lid itself: cracked, unlatched or missing. Homes that collect rainwater from the roof carry more risk; USGS advises disconnecting the gutter feed to the storage tank before cleaning the roof so ash doesn't wash into stored water.
Roof tiles and flat roof decks
We couldn't find any official report on ash thickness in Bekasi City. If the layer only looks like dust, roof load isn't the main issue; gutters and drains are. Don't climb onto the tiles of a two-storey house without fall protection. The cleanup guides published over the past week all make the same point: don't push it if the roof or the access isn't safe.
A sensible order: gutters first, then the AC outdoor unit, then the yard. All ash gets shovelled and bagged. None of it gets hosed into the drain.
Who Should Sit the Cleanup Out
Children, older people, pregnant women and anyone with a respiratory condition should stay out of it, according to guidance published by the state broadcaster RRI on 9 September. Whoever does the cleaning needs an N95 or KN95 mask, protective glasses, gloves and closed shoes. Skip fans and blowers indoors, since they lift particles that have already settled. A vacuum cleaner is fine if it has a HEPA filter; without one, fine particles can blow straight back out of the exhaust. For keeping indoor air cleaner in a two-storey house during dusty spells, we have a separate note on ventilation and filters.
Where the Ash Should Go
Collect it in closed bags or in one spot on open ground, away from any water channel. Don't dump it in drains, rivers or areas that usually flood. In a gated cluster, ask the estate manager or your RT (neighbourhood unit) whether there is a collection point, so bags of ash don't get mixed in with household rubbish and end up scattered on the estate road again.
If You're Viewing Houses This Month
Last week gives you a set of questions that rarely come up in a sales gallery. USGS notes that concealed (internal) gutters carry more risk because they are hard to reach for cleaning. So ask: are the gutters on this house exposed or built in, where can the downpipe be disconnected, and where is the drainage inspection box? Ask too where the AC outdoor unit will go and whether a technician can reach it without climbing a wall. For the wider question of estate drainage, see our note on modern housing drainage systems.
Kingspoint Private Residences sits on Jl. Raya Perjuangan in North Bekasi City, developed by Mandiri Development, about 5 minutes from Bekasi Station and Summarecon Mall Bekasi and about 10 minutes from the Bekasi Barat toll gate. The Emerald 70 house is ready stock: two storeys, 70 m² of floor area on a 47.25 m² plot measuring 4.5 m × 10.5 m, bored-pile foundation, priced around Rp 700 million including VAT, with instalments from Rp 5 million a month. Ask our team to walk you through the gutter line, downpipes and outdoor-unit position in the show unit.
Frequently Asked Questions
Can the volcanic ash that reached Bekasi damage a roof?
We couldn't find an official report on ash thickness in Bekasi City. With a thin layer, roof load is rarely the problem. Gutters and downpipes are more vulnerable; USGS says they can be affected by just a few millimetres of ash, especially once it gets rained on.
Can I clean volcanic ash by spraying it with water?
Dampening it lightly so it doesn't lift is fine. Hosing it until it runs into the drain isn't recommended, because ash builds up in drainage lines and can harden like cement. Shovel it up and bag it instead.
How long do AC filters need extra attention after ashfall?
USGS says filters may need replacing more often for several months after an ashfall. At home, check the indoor unit's filter more often than your usual schedule, and clean the outdoor unit's fins with dry methods.
Want to see the gutter line and AC position in the show unit?
The Kingspoint team can show you the gutters, downpipes, drainage inspection box and outdoor-unit mounting point on the ready-stock Emerald 70 house on Jl. Raya Perjuangan, North Bekasi.
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