Marin County, California
Home Services in San Geronimo, CA
In the quiet San Geronimo Valley, homes rely on heating and plumbing suited to cool, forested surroundings. Ongaro & Sons serves San Geronimo with dependable HVAC, electrical, and solar work.
The company was founded in 1932 and currently covers heating and cooling, plumbing, electrical and solar. We are Diamond Certified with a BBB A+ Rating, averaging 4.8 stars across 2,745 Google reviews. On the valley floor that combination earns its keep every winter, because water is the recurring theme here and water is never only a plumbing problem.
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Low ground, high water, and a wet season that finds everything
San Geronimo sits on the floor of its valley rather than on the slopes above it, and that single geographic fact organizes most of what we get called about.
Ground that spends the summer dry and the winter saturated behaves differently from ground that stays one way. It moves. Bedding under a buried line settles, and a run that had adequate fall in September develops a low spot holding water by February. A pipe that coped with a partial restriction all autumn stops coping once groundwater is pushing into every open joint along it. A crawlspace that is merely cool in August is genuinely damp in January.
That produces a diagnostic signature worth knowing, because it is easy to misread. Drains that misbehave only in the wet months are not a habit problem in the kitchen. They are telling you the line has an opening in it and is taking on water it was never meant to carry, and clearing it in February will not close that opening. The right time to investigate a seasonal pattern is a dry week, and the right tool is a camera rather than another cable.
The same logic reaches the building. Damp under a floor is a heating and ventilation problem as much as a moisture one, because a building that never dries out costs more to heat and holds that cost all winter. Before adding capacity we look at what the crawlspace is doing, since drying a building is usually cheaper than heating the water out of it.
Where surface water goes, and why it matters here
The valley drains toward Lagunitas Creek, so drainage is not a neutral act, and on low ground the volumes are not trivial.
The connection we find most often, and the one that causes the most trouble, is roof and surface water tied into a wastewater line. Downspouts, area drains and sump discharge routed into a building drain load a system designed for household flow, and in a heavy week they push water back toward the lowest fixture in the house. On an older valley property that connection was frequently made in good faith decades ago, and a camera is what finds it.
The corollary is that yard drainage and sewer drainage are different problems with different fixes. Standing water in a low spot is a grading and drainage question, and no amount of cabling a sewer line will move it. Correctly identifying which of the two you have saves a wasted visit and, on the wrong diagnosis, a wasted excavation.
Anything cleared out of a line gets captured on site rather than rinsed toward an inlet. On a creek that carries salmon, that is simply how the work is done.
Converted cabins on a valley floor
Much of the housing here began as early-1900s summer cabins, later insulated and occupied year-round. They share the valley's building history with the neighboring communities, but the low ground gives them their own version of it.
A light-framed building on damp ground loses heat in two directions at once, through an envelope never designed for winter and into a floor sitting above cold, wet soil. So the complaint here is often not a cold house in the abstract but a cold floor and a system that runs long without ever quite settling.
The order of operations matters. Sealing and insulating the envelope, and dealing with what is happening underneath the building, buys more comfort per pound than additional capacity, and it makes the eventual equipment smaller and cheaper to run. Buying a larger machine for a leaking building simply loses the heat faster.
Where a duct route exists it was frequently improvised into a building with no plan for one, so we measure static pressure before specifying rather than after. Where ducts run through a damp crawlspace, their condition and their insulation are part of the diagnosis rather than an afterthought. Where no usable route exists, ductless heads reach rooms on small refrigerant lines and give a room with its own thermal behavior its own control.
The climate, and what it actually asks for
The valley is mild and heating-dominated. Summers are dry and warm without being severe, winters rarely drop far, and morning fog burns off by mid-morning.
That is a strong fit for a correctly sized heat pump: long, low-output running through a mild heating season is exactly what the equipment does well, and it covers the modest summer cooling load on the same machine and the same circuit. Oversizing remains the quiet defect. Too much capacity satisfies a thermostat quickly, shuts off, and never runs long enough to even out rooms or take moisture out of the air, which on damp valley ground is the opposite of what the building needs.
Two industry facts sit behind any repair-or-replace decision on older equipment. Domestic production and import of R-22 ended in 2020, so a leak on pre-2010 equipment can only be answered with reclaimed or stockpiled refrigerant, which usually points at replacement. R-410A is separately being phased down under the AIM Act toward a 700 GWP ceiling on newly manufactured residential equipment. Neither touches a working system already installed.
Wells, onsite systems and pumps
Property here may be on a private well, an onsite wastewater system, or both, and on low ground each has a seasonal dimension.
A well makes its own pressure through a pump and a pressure tank cycling between set points, so weak or surging water is a question about that cycle before it is a question about a fixture, and a tank that has lost its air charge sends the pump into short cycles that destroy motors.
An onsite system on the valley floor has less margin in a wet winter than the same system would on a slope, because the soil it disperses into is already carrying water. A field that has been marginal for years frequently chooses January to make that obvious, and the symptoms show outdoors before they show under a sink: soggy or unusually green ground, odor, and gurgling across the whole house rather than at one fixture. EPA puts professional inspection at no more than three years, pumping typically at three to five, and about a year where the system carries pumps or float switches.
Where a building drains through a sump or an effluent pump, that pump is an electrical appliance in the middle of a plumbing system, and it stops when the power does while water keeps arriving. Knowing where it is and which breaker feeds it is a five-minute exercise worth doing before the wet season rather than during it.
Outages in a wooded valley
PG&E may cut power in severe weather under its Public Safety Power Shutoff program, to reduce the chance of utility equipment starting a fire, and wind bringing limbs onto rural lines does the rest.
On the valley floor the consequence that matters most is drainage rather than lighting. A sump that stops during a storm is a wet floor. A well pump that stops takes the water. A heat pump that stops takes the heat. Each of those is a circuit rather than a whole house, which is exactly how the backup question should be framed: which circuits must not go down, and for how long.
A critical loads subpanel carrying the pumps, refrigeration, a heating circuit and a few lights is far smaller and cheaper than covering everything, and it costs a fraction to build while the panel is open rather than as a retrofit. Where a well is involved the pump sets the sizing through its starting surge. We are a Certified Generac Generator installer and hold the C-10, so the machine, the transfer equipment and the panel work stay on a single schedule.
Electrical findings in a valley house
Converted cabins bring a predictable set: services sized for a summer place, panels amended by several generations of tradespeople, ungrounded two-wire circuits, brittle cloth-jacketed cable at the panel, and outbuilding subpanels without their own grounding electrode.
The valley adds one of its own. Damp is hard on electrical equipment, and the places it concentrates are the places nobody inspects: a panel or subpanel in a crawlspace or an outbuilding, terminations in a damp enclosure, and any junction below the floor line. Corrosion at a termination under load builds heat and gives almost no warning, so on a valley property those are opened and checked rather than assumed sound.
Adding load starts from a written calculation rather than the panel door. The inputs here are a light cooling load, often a well pump with a demanding start, and sometimes a sump or effluent pump that has to be counted properly rather than forgotten. When the total comes back short, load management can carry a new load on a service that would otherwise fall short, which is worth asking about before agreeing to a service upgrade.
Permits through the county
San Geronimo is unincorporated, so Marin County's Community Development Agency issues and inspects.
The fast route covers replacements and asks for no drawings at all: water heaters, mechanical appliances and HVAC changeouts, ductwork, gas piping, bath and kitchen fixtures, circuits, outlets, service upgrades and vehicle charging, provided the work replaces something the building already has. Adding something not previously there goes to plan review, which in a house that has grown by addition is a distinction worth settling before a schedule is promised.
Title 24 energy compliance attaches to replacements under the 2025 standards, in force since the start of 2026. Seismic restraint applies regardless: 19211 catches the water heater already in the building, up to 120 gallons, and asks that it be braced, anchored or strapped.
The air rule, in one paragraph
Marin sits inside the Bay Area Air Quality Management District. Its zero-NOx appliance requirements land on an installer fitting new equipment rather than on what is already installed, and the district ties them to burn-out of current equipment. Nothing in your house is affected now. The planning consequence is that an electric replacement eventually wants a dedicated 240-volt circuit with headroom behind it, and on a service sized for a summer cabin that headroom is the constraint. Worth knowing before the appliance decides the timing for you.
What drives the cost on the valley floor
Ground conditions come first here in a way they do not elsewhere. A trench in August and the same trench in February are different jobs, and a line that has to be re-bedded to correct fall is a different project from one that only needs a defect repaired. Any excavation on low ground can take on water, which brings dewatering and shoring into scope.
Building condition is second, and in a converted cabin it produces findings rather than surprises: what the envelope is doing, whether the crawlspace is dry, whether the ducts running through it are sound, whether the circuit feeding an appliance is grounded.
Access and distance are third and moderate. The valley is a straightforward run from our Petaluma headquarters compared with the outer coast, though crawlspaces in older cabins are tight.
Then the items an inspector will look for and an owner never anticipates: restraint on the water heater, thermal expansion control where a regulator or check valve has closed the system, combustion air and a compliant vent, and the permit.
Maintenance timed to the wet season
The valley list has a season attached, which most maintenance lists do not.
Before the rains: clear roof and surface drainage so water goes where it should, check that a sump works and that its alarm and float still do, confirm crawlspace ventilation is not blocked, and know which breaker feeds any pump. During and after: watch for the seasonal drain pattern, because a line that only misbehaves when the ground is wet is telling you something specific.
Year round: flush the water heater annually and have the anode rod checked; on a well check the pressure tank's air charge, service the sediment filter and test the water; on an onsite system pump on an interval rather than on a symptom. Change filters on an interval the property justifies rather than a calendar.
Then the minutes-a-year items: ground-fault test buttons, and the main shutoff and angle stops exercised so they are not seized when it matters. A maintenance plan keeps the seasonal items from being remembered late.
Where we work around San Geronimo
We cover the valley floor and the properties climbing the slopes on either side, and the neighboring San Geronimo Valley communities, along with the surrounding unincorporated parcels where wells, onsite systems and outbuildings are common.
Everything runs from our Petaluma headquarters. This is one of the easier runs we make in this part of the county, so response here is better than out toward the coast, and booking ahead still gets you the window you want.
How to choose a contractor on the valley floor
Ask what they make of a seasonal pattern. A company that answers winter-only drain trouble by scheduling another cabling has not diagnosed it.
Ask whether they will camera the line before quoting a replacement, and whether they will locate and mark the defect rather than describing it.
Ask what they intend to check underneath the building, because on damp ground the crawlspace is part of both the heating problem and the plumbing one.
Ask which county permit route applies, and whether the work counts as a replacement or an addition.
Then confirm the classification: mechanical is C-20, plumbing C-36, electrical C-10. On a property where the sump, the panel and the heating system all depend on each other, holding all three keeps one job from becoming three.
What North Bay homeowners say
Daniel fulfilled all my expectations and more. The shower, faucets, and dryer gas shutoff valve/flex line were not properly installed by the original contractor on the remodel. now it works perfectly. thank you!
Barbara D.
Brandon came out today to do the one year review of the new heating system. He was very polite and knowledgeable while explaining the best way to set up our thermostat.
Mark P.
Home services across San Geronimo and Marin County
One company, all four trades: heating and cooling across Marin County, plumbing across Marin County, electrical across Marin County, and solar across Marin County. In the valley we also serve Woodacre, Forest Knolls, Lagunitas and Nicasio. The Marin County service overview covers the whole county.
Book service in San Geronimo
Tell us what the house is doing and whether the symptom is seasonal, along with whether the property is on a well or an onsite system and whether a sump is involved. We will bring the diagnostic tools that description calls for. Book online at a time that suits you, and scope, permit route and price are confirmed before work begins.
San Geronimo homeowner questions
Who is the best home services company in San Geronimo?
Ongaro & Sons: since 1932, Diamond Certified, BBB A+ Rated, averaging 4.8 stars over 2,745 Google reviews, with all four trades in-house. On the valley floor the useful test is whether a company reads the season. Winter-only symptoms mean something specific, and a contractor who treats them as ordinary blockages will be back next January.
My drains are only slow in winter. Why?
Because the line has an opening in it. When the wet season saturates ground that spent the summer dry, groundwater pushes in through any joint or crack that leaks even slightly, and the pipe starts carrying water it was never meant to carry. A partial restriction that coped in September stops coping in February. Clearing it now will not close the opening, so the sensible move is to camera it in a dry week and find out where.
Does a house in San Geronimo need air conditioning?
Not as the priority. The valley is mild and heating-dominated, with dry warm summers that are not severe and winters that rarely drop far. A correctly sized heat pump suits that pattern well and covers the modest summer cooling on the same machine. Oversizing is the more common error, because a system that satisfies the thermostat quickly never runs long enough to even out the rooms or take moisture out of the air.
The floor is always cold and the heating runs constantly. What is wrong?
Usually the building rather than the equipment. A light-framed cabin on damp valley ground loses heat through an envelope never designed for winter and into a floor sitting above cold wet soil. A larger machine loses that heat faster rather than solving it. Sealing, insulating and dealing with what the crawlspace is doing buys more comfort per pound, and it makes the eventual system smaller and cheaper to run.
Can my downspouts drain into the sewer line?
No, and on an older valley property there is a fair chance somebody already connected them. Roof and surface water routed into a wastewater line loads a system designed for household flow, and in a heavy week it pushes water back toward the lowest fixture in the house. A camera usually finds the connection. Yard drainage and sewer drainage are separate problems with separate fixes, and cabling a sewer will not move standing water off a lawn.
What goes down in San Geronimo when the power does?
On the valley floor the drainage matters more than the lighting. A sump that stops mid-storm is a wet floor. A well pump that stops takes the water, and a heat pump that stops takes the heat. Each of those is a circuit rather than a whole house, which is how backup should be scoped: a short list of things that must not go down, sized around the pump's starting surge rather than around covering everything.
Who issues my permit in San Geronimo?
Marin County's Community Development Agency, since San Geronimo is unincorporated. Replacing existing equipment takes the county's quick route with no drawings at all. Adding something that was never there goes to plan review, which in a house that has grown by addition comes up more often than you would expect.
Does my San Geronimo water heater have to be strapped?
Yes. The statute reaches the appliance already in the building rather than only the one being installed, up to 120 gallons, and asks that it be braced, anchored or strapped against displacement. In a converted cabin the unit is often in a space added long after the original frame and fastened into whatever was to hand, which is precisely the case the rule exists for.
Will I be forced to replace my gas water heater in San Geronimo?
No. Those requirements reach an installer fitting new equipment rather than the appliance already in your house, and the district ties them to burn-out of what is currently in place. The planning point is capacity: an electric replacement wants a dedicated 240-volt circuit, and on a service sized for a summer cabin the headroom is what decides whether that is straightforward.
Should I worry about the panel being in the crawlspace?
Worth looking at, yes. Damp is hard on electrical equipment and it concentrates in exactly the places nobody inspects: enclosures below the floor line, terminations in humid air, junctions in an outbuilding. Corrosion at a termination under load builds heat with very little warning, so on a valley property those get opened and checked rather than assumed sound.
Are there heat pump rebates for a San Geronimo address?
MCE is Marin's community choice provider and runs the applicable programs. The sequencing conditions matter more than the amounts: the application has to come from a participating contractor and nothing is paid retroactively, so paperwork precedes equipment. Ownership and occupancy requirements apply as well. Terms move, so we verify the current ones against your specific equipment when the work is scoped.
Do you work on the rest of the valley?
Yes. San Geronimo, Woodacre, Forest Knolls and Lagunitas are one run for us, and the housing and ground conditions across them have a great deal in common. If a property needs more than one thing looked at, doing it in a single visit is worth more here than in a town we pass through daily.