Marin County, California
Home Services in Kentfield, CA
Kentfield's wooded lots and established homes call for skilled, careful service. Ongaro & Sons brings trusted heating, cooling, plumbing, and electrical expertise to this quiet corner of the Ross Valley.
A 1932 North Bay company, Ongaro & Sons now runs heating and cooling, plumbing, electrical and solar itself rather than subcontracting them. Diamond Certified with a BBB A+ Rating, and 2,745 Google reviews averaging 4.8 stars. In one of the wettest places we work, that matters because the moisture problem and the heating problem and the drainage problem in a Kentfield house arrive together rather than separately.
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Unincorporated, surrounded by towns that are not
Kentfield sits on the eastern slopes of Mount Tamalpais, and it is unincorporated. That is easy to miss, because the communities around it are not, and a Kentfield address sits close enough to Ross, Larkspur and San Rafael that people reasonably assume one of them handles the paperwork.
None of them do. Building permits and inspections here come from Marin County's Community Development Agency, and that is worth establishing before anything else, because the county's process differs from a town's in a way that helps you.
The county runs two routes and the distinction is replacement versus addition. Where work replaces something the building already has, no drawings are required at all: the application is the whole submission and the permit issues at the speed you can complete it. Water heaters, mechanical appliances and HVAC changeouts, ductwork, gas piping, bath and kitchen fixtures, circuits, outlets, service upgrades and vehicle charging all sit in that category. Adding something not previously there goes to plan review instead.
That means a straightforward changeout here closes out faster than the same job a few hundred yards away in an incorporated town. It also means a contractor who works mostly inside town limits may quote your schedule from the wrong process. We confirm the parcel before writing anything.
Among the wettest spots in the Bay Area
Kentfield takes rainfall in the region of forty-eight inches a year, which puts it near the top of the range anywhere around the bay. That single figure reorganizes the priorities on a house here.
The obvious consequence is drainage, but the one people underestimate is what sustained moisture does to a building's heating requirement. Damp air takes considerably more energy to bring up to temperature than dry air, and a building that never fully dries between storms carries that penalty right through the season. So a house that feels cool and clammy with a system running constantly is usually not describing an undersized system. It is describing a moisture problem being answered with heat.
The productive order is therefore moisture and envelope first, capacity second. What the crawlspace is doing, whether its ventilation is blocked, whether surface water is being carried away from the building or toward it, and whether ducts running through a damp underfloor space are sound and insulated. Those are cheaper to fix than they are to heat around, and they make the eventual equipment smaller rather than larger.
The mechanical brief itself is mild. Warm dry summers and cool wet winters mean heating carries most of the year with a modest cooling requirement, which is exactly the profile a correctly sized heat pump handles well: long low-output running, which also does more to even out and dry a house than a system that satisfies the thermostat quickly and stops.
Slope, and where the water goes
Kentfield runs from the flatter ground near the creek up onto the eastern slopes of the mountain, and a property's position on that gradient changes the work.
On the slope, water moves fast. A buried lateral running downhill carries water quickly and can leave solids behind on the way, which is a different failure from the standing-water bellies of flat ground. Surface water arrives at the downhill side of a building with force rather than pooling gently, so grading, area drains and how they discharge matter more than they would on level ground.
On the flatter ground, the opposite applies: water arrives and stays, ground saturates for months, and bedding under buried lines settles so that a run with adequate fall in September develops a low spot by February.
Both produce the same seasonal signature, and it is worth recognizing because it is easy to misread. A drain that misbehaves only in the wet months has an opening in it and is taking on groundwater it was never designed to carry. Clearing it in February will not close that opening, so the useful move is a camera in a dry week.
Roof and surface water tied into a wastewater line is the other recurring find. On older property here that connection was frequently made in good faith decades ago, and in a heavy week it pushes water back toward the lowest fixture in the house. Yard drainage and sewer drainage are separate problems with separate fixes, and no amount of work on a sewer line will move standing water off a lawn.
Older housing on a wet hillside
The housing here is largely older detached single-family stock, a good deal of it from the 1950s or earlier, and the findings follow that.
Services sized for a much smaller electrical appetite, panels amended by several generations of tradespeople, ungrounded two-wire circuits behind modern-looking receptacles, and cloth-jacketed cable gone brittle where conductors flex into the panel. On the plumbing side, galvanized supply that has closed from the inside so flow is weak everywhere at once, and cast iron waste scaled toward a fraction of its nominal bore.
There is a wet-climate layer on top of that here which drier parts of the county do not carry. Humidity attacks electrical connections, and it does so in the parts of an installation nobody ever opens: a box under the floor, a subpanel in an outbuilding, a lug in an enclosure whose gasket gave up years ago. What makes that dangerous rather than merely untidy is that a corroded connection carrying load generates heat, and it does so almost silently until it does not. On a Kentfield property those get opened rather than trusted.
Where ductwork exists it was usually improvised into a house framed long before central air, so static pressure gets measured before anything is specified. Where ducts run through a damp crawlspace their condition and insulation are part of the diagnosis rather than a detail. Where no usable route exists, ductless heads reach rooms on small refrigerant lines without opening ceilings.
Where Kentfield water comes from
Kentfield sits inside Marin Water's central and southern Marin service area, and the supply is a blend. Roughly three quarters originates as rainfall on the district's protected Mt. Tamalpais watershed, which is directly above this community, and on the west Marin hills. The remainder is purchased from the Sonoma County Water Agency off the Russian River system.
Hardness differs between the two: the district's reservoir water averages around 3.5 grains per gallon and the Sonoma supply about 6.5. Neither is severe, so aggressive treatment sold on a hard-water premise deserves scrutiny here. But the proportion varies, which is why a tankless descaling interval belongs on what we actually find on the heat exchanger rather than on a chart.
Marin Water also publishes water efficiency rebates, and one is directly relevant to plumbing work: a rebate toward a hot water recirculating system. On a house with a long run to a distant bathroom that is worth pricing alongside a water heater replacement rather than afterwards, because retrofitting means opening things twice.
Electrical work and the load calculation
Nothing gets added to a service here on the strength of what is printed on the panel door. The arithmetic starts with square footage for lighting and receptacles, brings in each fixed appliance at whatever demand factor the code permits for it, takes heating or cooling as a single figure rather than adding the two, and then holds that total against the capacity the service can supply.
Where the number comes back short there are two roads. A service upgrade is right where the service is at its limit or the panel is obsolete, damaged or out of legitimate space. Listed load management equipment is the other, watching whole-house draw and limiting a large load when the rest of the house pulls hard, which changes what the calculation must accommodate. On a hillside property where relocating a service is awkward, that alternative is frequently the better project as well as the cheaper one.
On low-lying parts of a parcel, panel position deserves a second look at the same time. A service or subpanel mounted low on a garage wall is a decision somebody made once, and a replacement is the practical moment to reconsider it.
Outages, pumps and backup
A deliberate outage is possible in severe fire conditions, under PG&E's Public Safety Power Shutoff program, and a wooded hillside community loses power to falling limbs as well.
On municipal water the taps keep running, so the consequences are refrigeration, heating and any pump. In this rainfall the pump is the one that matters. A sump stopping during a storm is the failure that costs real money, because the weather causing the outage is the weather making the pump necessary, and a lower-level ejector pump has the same exposure.
The right way into that conversation is a list, not a catalog. Write down what genuinely cannot go down, which on a property here is usually the sump, the refrigerator, one heating circuit and enough lighting to live by, and size around that. A subpanel serving those costs a fraction of covering the building, and a fraction again if it is built while the main panel is already open for other reasons. Whether the source is a battery or an engine is the easier question, and it turns on how long your outages last rather than on preference. We are a Certified Generac Generator installer and hold the C-10, so whichever route fits, the equipment and the panel work stay on one schedule.
The air rule, briefly
Marin sits inside the Bay Area Air Quality Management District, so its zero-NOx appliance requirements reach here. They attach to the moment an installer fits new equipment, on dates arriving by appliance type, and the district ties them to burn-out of what is currently in place. The amendments are unfinished and nothing already installed is affected.
The consequence worth planning for is capacity rather than compulsion. An electric replacement eventually wants a dedicated 240-volt circuit with headroom behind it, and on a mid-century service that headroom is the constraint. On a property that may also want a sump circuit protected, knowing the number early is what keeps the decision yours.
Solar under the mountain
State law obliges the county to run a streamlined process for small residential rooftop systems, approve a complying application administratively, and keep review inside health and safety, under Government Code 65850.5.
The design questions here are terrain and trees. On the eastern slopes of the mountain, shading comes from topography as well as canopy, and both vary by month in ways an annual average conceals. A study done plane by plane and month by month is the only kind worth having.
What an array is worth changed too. Interconnection applications from April 2023 onward fall under the Net Billing Tariff, and the shift it made is that exported energy is now credited at whatever it happens to be worth to the grid in that particular hour, which is very little in the middle of the afternoon. The design consequence is that a system is sized against household consumption rather than roof area, and that storage stopped being an upgrade and became part of a sensible design.
What drives the cost in Kentfield
Moisture-related condition leads, and it produces findings rather than surprises: what the crawlspace is doing, whether ducts running through it are sound, whether an enclosure has been sitting in damp air, whether a termination has corroded.
Slope and access come second. A crawlspace that is generous at one end and impassable at the other, equipment carried rather than wheeled, and drainage work that has to account for water arriving with force rather than pooling.
Scope is third: a like-for-like swap stays in one trade, while a fuel switch or a tankless conversion brings gas sizing, venting, condensate and often a 240-volt circuit with a panel calculation behind it.
Then the items every inspection checks and no homeowner budgets for: restraint on the water heater, thermal expansion control where the system is closed, combustion air and a compliant vent, and the permit fee.
Maintenance in a wet climate
The pre-rain list matters more here than almost anywhere. Confirm that roof and surface drainage carries water away from the building, that crawlspace ventilation is not blocked, and that any sump works along with its float and alarm. Know which breaker feeds it.
Year round, flush the water heater annually and have the anode rod checked. Set a tankless descaling interval from what we find rather than from a chart, since the supply is a blend. Change filters on an interval the property justifies, and have the capacitor and contactor tested before the first warm week.
Where mature trees stand over a buried lateral, camera it every few years rather than waiting for a second backup. And keep the minutes-a-year items current: 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 half from being remembered late.
Where we work in Kentfield
We cover the flatter ground near the creek and College Avenue, the streets climbing the eastern slopes of the mountain, and the surrounding unincorporated pockets, along with the neighboring towns where the permitting authority changes even though the drive does not.
Everything runs from our Petaluma headquarters, and central Marin is a straightforward run. Booking ahead gets you the window you want, and on a hillside property we would rather assess everything in one visit than stage twice.
How to choose a contractor here
Ask whether they have confirmed that Kentfield is unincorporated. It sounds pedantic and it is not: a contractor who assumes a town issues your permit will quote your schedule off the wrong process.
Ask what they will look at before quoting capacity, because in this rainfall a cool clammy house is usually a moisture problem being answered with heat.
Ask what they intend to check in the crawlspace, since on a wet hillside that is where the plumbing diagnosis, the duct diagnosis and often the electrical one all live.
Ask what they make of a seasonal drain pattern, because winter-only symptoms mean something specific.
Then confirm the classification: mechanical is C-20, plumbing C-36, electrical C-10, and holding all three is what keeps a job where the sump, the panel and the heating all touch each other from becoming three schedules.
What North Bay homeowners say
We have a home on the Sonoma Coast with difficult salt air conditions. Ongaro guys diagnosed a tough situation and proposed some reasonable solutions to get our hot water boiler back online. Good job!
Mark F.
Repairman Anthony was sent to my home and arrived on time. He was extremely professional, had great customer service skills, and excellent HVAC knowledge. He is highly recommended as is Ongaro & sons. Thank you.
Abe J.
Home services across Kentfield 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. Nearby we also serve Ross, Larkspur, Greenbrae and San Anselmo. The Marin County service overview covers the whole county.
Book service in Kentfield
Tell us what the house is doing, where it sits on the slope, and whether the trouble is seasonal. If the complaint is comfort rather than a breakdown, mention what the crawlspace is like, because in this rainfall that is usually where the answer is. Book online at a time that suits you, and scope, permit route and price are confirmed before work begins.
Kentfield homeowner questions
Who is the best home services company in Kentfield?
Ongaro & Sons: Diamond Certified, BBB A+ Rated, 2,745 Google reviews averaging 4.8 stars, and four trades run under a single license in a company founded in 1932. In this rainfall the sharper test is diagnostic: whether a company investigates moisture before selling capacity, and whether it knows Kentfield is unincorporated so it quotes your schedule off the right permit process.
Who issues my permit here, given the towns all around?
Marin County's Community Development Agency, because Kentfield is unincorporated even though Ross, Larkspur and San Rafael are close by. That works in your favor: the county requires no drawings at all where the job replaces something the building already has, and the permit issues at the speed the application is completed. A contractor who assumes a town department is involved will describe a slower process than the one you face.
My house feels cool and clammy and the heating runs constantly. Is the system too small?
Usually not. Kentfield takes something like forty-eight inches of rain a year, and damp air needs far more energy to warm than dry air, so a building that never fully dries between storms carries that penalty all season. The system is working against moisture rather than against the cold. Ventilation, crawlspace condition and surface drainage are cheaper to fix than to heat around, and correcting them lets the eventual equipment be smaller.
Does a house in Kentfield need air conditioning?
A modest amount. Summers are warm and dry, winters cool and wet, so heating carries most of the year with a real but moderate summer cooling requirement. A correctly sized heat pump covers both on one machine, and long low-output running is also what dries and evens a house, which matters more here than in a drier part of the county.
My drains are only slow in winter. What does that mean?
That the line has an opening in it. When the ground saturates, groundwater pushes in through any joint or crack that leaks even slightly, and a pipe that coped in September stops coping in February. Clearing it now will not close that opening. The productive step is a camera in a dry week, and while it is in there it is worth checking whether roof or surface water has been connected into the line, which is a common find on older property here.
Is the water hard?
Not particularly, and it is a blend. Marin Water takes roughly three quarters from its own Mt. Tamalpais and west Marin reservoirs at about 3.5 grains per gallon, and buys the rest from Sonoma County off the Russian River at about 6.5. The proportion varies, and so a tankless descaling interval should come from what we find on your heat exchanger rather than from a generic figure, and why treatment sold as necessary here deserves a second look.
Should I worry about the panel in the crawlspace?
Worth having it opened, yes. In this rainfall the electrical trouble is not usually in the visible parts of an installation; it is in a box under the floor or a subpanel in a shed, where humid air has been working on the connections for years. A connection that has corroded while carrying load runs hot, and it gives very little warning before it stops being a nuisance and starts being a hazard.
What happens in Kentfield when the power goes out?
Water is not the problem here, since the district's supply arrives under its own pressure. What goes is anything cold, anything warm, and anything that pumps. In this rainfall the pump is the one that matters, because a sump stopping during a storm is exactly the failure you cannot afford, and the weather causing the outage is the weather making the pump necessary. Backup is best scoped as a short list of circuits rather than whole-house coverage.
Does my Kentfield water heater have to be strapped?
Yes. The 120-gallon ceiling in Health and Safety Code 19211 applies to what is already installed as well as to what is being installed, and the appliance has to be braced, anchored or strapped against displacement. In older housing the unit is often in a space added long after the original frame, fastened into whatever was to hand, which is the case the rule exists for.
Will I be forced to replace my gas water heater in Kentfield?
No. The Bay Area district's requirements attach to an installer fitting new equipment rather than to anything already in the building, the district ties them to burn-out of current equipment, and the amendments are unfinished. What is worth planning for is capacity, since an electric replacement wants a dedicated 240-volt circuit and on a mid-century service the headroom is what decides how straightforward it will be.
Is solar worth it on the eastern slope?
It can be, but the study has to account for terrain as well as trees. On the slopes below the mountain, shading comes from topography as much as canopy, and both change through the year in ways an annual average hides. A proper study is done plane by plane and month by month. Under current export rules the design follows what the house consumes rather than what the roof could produce, and so storage is now a normal part of a well-designed system.
What rebates reach a Kentfield address?
Two sorts from two bodies. MCE, the county's community choice provider, runs the electrification programs, and the order of operations matters: a contractor from their list files the application, it precedes the installation because nothing is paid retroactively, and ownership and occupancy tests apply. Marin Water separately publishes water efficiency rebates, including one toward hot water recirculation, which is worth planning alongside a water heater rather than after it.