Hello, this is DIY Renova.

In this article, we will explain in detail, including specific examples and engineering points, so that even beginners can perform a certain amount of work if they read this article, with the theme of "self-renovating water-related homes intended for Japanese wooden houses (up to two-story buildings).The content is full of content, including the "Legal risks when messing around with water in DIY," "measures when you want to create new plumbing without breaking the floor," and "prevention of freezing measures," which were discussed in a previous conversation.Please read to the end.

The content written here is based on Japanese laws and local government ordinances.There are further advanced construction methods overseas, but in Japan, water supply equipment construction is generally carried out by designated contractors under the ordinance.I'm writing this with the stance of "the extent to which I can do it with DIY" and "If you're going to do it, be careful here."If you are doing extensive plumbing work, be sure to consult your local waterworks bureau or a qualified professional.We recommend making careful decisions to avoid legal risks (not covered by insurance, violations of management regulations, etc.).

Although this article has a large number of characters, I have written in detail so that you can take action without hesitation once you read this.We have organized specific construction methods and procedures in step format so that they can be used as a reference, so be sure to bookmark them and read them over and over again.

Well then, let's go!

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There are surprisingly few things that can be done legally through DIY.

First, let's talk about the basic premise.According to Japanese laws and regulations, in many areas, only companies registered with local governments as "designated water supply equipment construction (piping after the meter)" can be performed by many regions.Specifically, replacing old water pipes, changing the pipe route, and new branching to add faucets... these tasks must basically be left to a "qualified operator."

Some people may think, "Is this okay because it's not an expansion, but a relocation?"However, under the ordinance, "relocation (change of position)" and "change of diameter" also fall under "modification", and as a general rule, DIY is not permitted.The expressions may vary depending on the city, town, or village, but almost all of them use the same rules.

However, it is also true that "minor repairs," "smooth gasket replacement," or "simple replacement with the same faucet" are permitted (in some local governments, this may be stated in the regulations).In this article, we will explain things like "What you can do with DIY" and "What you should check in advance if you do it," but in the end, make sure to prioritize the rules of each local government or management association.

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If you do not follow the rules, criminal penalties will not be enough, and you will no longer be able to use your home insurance when there is a problem!

Many people think, "If you violate the ordinance, it won't cause any trouble with the police, right?"In fact, there are rare cases where the incident is treated as such a major incident, but that doesn't mean you can be at ease.If a serious water leak occurs as a result of tinkering with pipes using DIY, the following risks arise:

1. "Home property insurance, fire insurance, etc. are not covered due to inappropriate construction."
2. "Apartments or rentals can lead to violations of management regulations, orders to restore the property to its original state or claims for penalty."
3. "If damage occurs to the neighborhood or the lower floor, there is a high chance that a claim for damages will be raised."

When a major accident occurs due to a DIY violation of the ordinance, the insurance company may not pay the insurance claim, saying that the construction was not appropriate.Furthermore, it is entirely possible that the leak will spread to the lower floor, causing you to be held liable for high compensation.Although "criminal penalties are small," the economic burden as a real harm can be quite heavy.

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Status check

So, where should you start specifically?First, check the status.By keeping the following points in mind, you can get a guideline whether you can fix it with DIY or whether you should leave it to a professional.

Check "1. What is the material?", "2. How much rust and corrosion is there?", "3. If there is water leakage," and "4. If the piping route branching is not complicated."

Is the material iron?

In older houses, "galvanized steel pipes" (so-called iron pipes) may be used for the pipes.This is because of aging, rust occurs on the inside, causing extreme water pressure and problems such as rust mixed in with water.If it is already 30 or 40 years old, use the following method to check the materials:

1. Open the under-sink or under-floor inspection port
2. Check visually and with touch (galvanized steel pipes are silvery metal pipes, but the surface may be rough).
3. Try bringing a strong magnet closer (iron material will have a magnet)

If the iron pipes are used, if the rust becomes severe, the internal diameter will become extremely narrow and there is a risk of the water volume being reduced.In addition, the rust cracks can cause pinholes to open and water leakage.It would be ideal to immediately replace it with a PVC pipe or resin pipe (HIVP pipe, polyethylene pipe, etc.), but here, consider whether it is within the range that is acceptable for DIY.Generally, "replacement of iron pipes with plastic pipes" is a large-scale construction project, so it is safer to ask a designated contractor.

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Repair edition

There are several areas where you can do "minor repairs" by DIY.Typical examples include "replacing the faucet (mixer faucet) itself," "replacing the gasket," and "inspection and repairing water leaks."However, make sure you have to stop the water before doing this, and make sure you check whether a notification with the Water Bureau is not necessary.

Furthermore, major modifications, such as changing the water supply position from the second floor to the first floor, are almost certainly required under the ordinance to be constructed by designated construction companies.If it is determined that it is beyond the scope of DIY, please contact a specialist.

Basically, contact the water supply department for water pipes.

When switching part of the pipes or fixing a serious leak, it is most reassuring to contact the designated water supply system construction company designated by the Water Bureau before making it at your own discretion.You can easily search on the local government's website or phone book.If you feel that the estimated amount given by a designated store is high, it is a good idea to ask multiple companies to get a quote.

However, many people do "really minor repairs" by DIY.For example, the following example:

1. "Replace the faucet (same size, same type)"
2. "Replace the water supply hose under the sink"
3. "Replacing an old packing (O-ring)"

Many families actually do this kind of behavior through DIY, and there are many cases where local governments effectively acquiesce (this is just a gray area).However, if a serious accident occurs, you are responsible for your own risk, so if construction procedures or techniques are not involved, do not overdo it and ask a specialist.

If you want to change from old iron pipes to comfortable materials

For example, if you want to change old iron pipes to PVC pipes or cross-linked polyethylene pipes, DIY is likely to result in a major piping change, so an official notification will likely be required.
For reference, if we are to list an engineering perspective,
"If the inner diameter of the water supply pipe narrows from 13mm to 10mm, the flow rate will drop significantly even at the same water pressure (calculations suggest that water volume decreases by more than 10% to 20% due to increased fluid resistance)."
Be careful when changing the pipe diameters like this, as they may vary with the water meter diameter.It can be said that there is a great risk to do it DIY.

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Preparation

Here we will introduce maintenance to prepare for disasters and cold waves, such as "freezing measures" that are common in winter.These are relatively easy to tackle even in DIY, and are often treated as "minor repairs."

Prevents freezing

If it is a two-storey wooden building, in an area where the outside temperature drops to a few degrees Celsius, exposed outdoor pipes and water pipes near the second-floor balcony may freeze.If it freezes, in the worst case, it can burst and cause serious leakage.As a measure, follow the steps below.

1. If you have a "water drain plug", drain the water at night or when you are away for a long period of time
2. Always wrap heat-insulating materials (expanded polyethylene tubes and insulation materials) around exposed pipes and secure them with vinyl tape.
3. When the room gets extremely cold, keep the water flowing small amounts at a time (prevents the water supply pipe from stopping movement).
4. If there are areas where the pipes that run through the attic or under the floor are prone to getting cold air, add insulation.

(Engineering rationale: Water expands by about 9% in volume at around 0 degrees, so if it freezes inside the tube, it often causes strong pressure to apply, leading to tube rupture. It is important to use heat-insulating materials to relieve the outside temperature and prevent it from falling even slightly below the temperature.

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If you want to start a new piping without destroying the floor

As I have mentioned in this article several times, major construction projects such as "I want to lay new underfloor pipes" and "I want to move the faucet on the second floor to the first floor" are likely to fall under the regulations and are subject to restrictions on DIY.However, here are the "methods" and "thinking" to add plumbing without destroying the floor.Please use this as a reference only (please ask a designated contractor for actual construction).

"Method 1: Exposed Piping"

1. Use a mall or piping cover to crawl the surface of the wall without passing through the wall or attic.
2. Choose weather-resistant HIVP pipes or stainless steel pipes for piping materials
3. For drain pipes that require a slope, a slope of about 1/50 to 1/100 (2cm to 1cm/m) is ensured.
4. If you are concerned about the appearance, try using it to pass through the back of a piping mall or furniture.

"Method 2: Plumbing using walls and attic spaces"

1. Consider a route to pass through the wall inspection port and attic (attale) without destroying the floor.
2. Create a minimum required small opening and piping through it.
3. Be careful not to damage the building structures (beams, columns, and braces).If you drill holes in areas that are important in structural calculations, the strength will be reduced, so be sure to seek expert judgment.

"Method 3: Using the Pump"

1. If the gravity gradient cannot be achieved, use a small drain pump to push the water up.
2. If you do not choose a pump with sufficient power, you will be insufficient to water pressure, so be sure to check the product specifications (lifting head and flow rate).
3. Since pumps are electrical appliances, you need to secure a power source.Don't forget to prevent leakage and install grounding

Please note that since all of these construction methods have a large scope of construction, in many cases it is necessary to report it to the local government or to obtain approval of the management regulations.

Can you remove unused septic tanks?Can you dig it up with DIY?

When you self-renovate an old house, you may find that "old-time septic tanks" are still buried in the exterior or part of the garden.this is,Houses that have switched from septic tanks to public sewer systems in the pastThis is a common phenomenon.

First, I will explain from the perspective of, "Is it okay to leave it as is?" and "Should I remove it?"

What happens if a septic tank is left unattended?

• Even if an unused septic tank is buried in the ground,It's not immediately illegal.
  However, due to the following problems,Removal or appropriate "backfilling" is recommended.

1. Risk of sinking
   The ceiling of the concrete septic tank that has been left unattended for a long period of time has deteriorated.It may not be able to withstand the weight and may cave.It's especially dangerous when there are people or cars on top of it.
2. Issues of bad odors and residual sludge
   Inside the septic tankUntreated sludge and waste residues can cause rot and foul odors and soil contamination.Becomes.
3. It may become a problem when rebuilding or selling
   "Houses with septic tanks still intact" are sold or rebuiltThere may be obligations to notify or remove.

What kind of work is required to remove a septic tank?

Basically, there are two patterns:

[A] Complete removal (removal of septic tanks from the ground)

Procedure (assuming contractor construction)

1. Excavate the ground with heavy machinery (mini backhoe, etc.)
2. Remove the septic tank, cut the concrete tank and transport it out.
3. Level the ground, backfill (crushed stone + soil) + compression treatment
4. Finally, redeveloping the exterior of the garden and parking lot.

Estimated cost (request for a contractor)
・Around 300,000 to 600,000 yen (depending on region and ground)
・There may be variations in concrete thickness, presence or absence of residual sludge, and ease of access

Is DIY possible?

• HonestlyCan't recommend it.
• The reasons are as follows:
  • Concrete septic tanks weigh over several hundred kg
  • Because it is buried deep in the ground, the amount of excavation is large (deep 1.5m or more)
  • Heavy machinery such as a backhoe is required (licence required)
  • If there is sludge remaining,Needs to be treated as industrial waste

Legally,Removal of septic tanks and disposal of sludge are subject to regulations under the "Septic tanks Act" and "Waste Disposal Act."Therefore, it is practically quite difficult for individuals who are not licensed companies to do this.

[B] Buried (refilling the septic tank as is and rendering it unusable)

Complete removal is costly and time-consuming.A more realistic way to "bury"(=Refilling the product in a state that is unusable) is widely carried out.

Procedure (contractor or partially DIYable)

1. Open the lid of the septic tank and check the inside
2. Sludge and water inside are suctioned (required by a contractor, such as a vacuum car)
3. High pressure cleaning inside the septic tank (removal of odors and residues)
4. InsideFill with gravel, crushed stone, soil, etc.
5. Cover the ventilation pipes and pipes and compress the top to complete the process.

Estimated cost (request for a contractor)
・Around 100,000 to 200,000 yen (depending on the content)
・Vacum fee + cleaning + backfill + ground leveling

What is the extent to which DIY can do?

• If you only need to clean the interior and refill the soil, we can handle some of the work (but it is your own responsibility).
• Since only licensed professionals are allowed to handle sludge suction and industrial waste disposal, at the very least, this part must be outsourced to a certified contractor.
• You can also procure and fill up gravel and soil yourself at a home improvement store.Compacting using a "compression machine" is also recommended to prevent sinkholes.(Simple rental available)

If you want to handle it with DIY, how do you proceed (step-by-step guide)

1. Check where the septic tank is (if there is no drawing, insert a metal rod into the garden to find it)
2. Open the lid and check the internal situation (the lid is heavy, so two people work with it)
3. If there is sludge or residual water, please contact a "septic tank cleaning company" or "vacuum contractor" (a licensed local government company is required)
4. Once the inside is empty, add several tens of cm of gravel or soil and turn it into pressure each time (weight + thrust is OK, but the ideal use of a plate compactor)
5. Once you've refilled to the surface, you can finish the top with mortar, weed-control sheet + gravel.

Legal and notifications to be aware of

• According to Articles 12 and 33 of the Septic Tank Act, "If the use of a Septic Tank is abolished, the local government will be required toNotification is required" (If you fail to submit a notification, you will be subject to instruction)
• "Abolition Notification" is in the municipal sewerage department and the Environment Division.
• Even if you do the removal or refill work yourself, you will need to notify us (free of charge)

Maybe they're leaving the septic tank alone?If you think so

If you have a "mysterious concrete lid," "only a part of the garden easily sinks," or an empty tank with no pipes connected," during self-renovation, first check whether it is an "old septic tank."
By ordering drawings, local government's "sewer switching records" and "septic tank ledger," you may be able to understand where and what is.

Conclusion: It is difficult for amateurs to remove it, but if the correct arrangements are made, it is possible to "bury" it.

・Complete removal, which requires heavy equipment, is unrealistic for DIY (dangerous + legal restrictions).
・It may be possible to handle the issue if partial DIY and partially asked for a "burying"
・Always properly dispose of sludge (do not fill it up without permission)
・Don't forget to submit a notification of abolishing the use of septic tanks

At first glance, a septic tank looks like a simple "concrete structure",It is a major problem if not properly dealt with both legal and hygienic conditionsIt will become.If you discover it during your self-renovation, don't panic and follow the steps and draw a clear line on what to do with a DIY project and what to do with a contractor.

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Conclusion

How was it?This time, we focus on "water-related maintenance, repairs, and checks that can be done at your own home."

"What is the real extent of DIY allowed?"
"Examples of large-scale construction work that you should not (do not) do"
"What to do with old iron pipes?" "Preventing freezing"
"The idea of ​​creating new plumbing without destroying the floor"

We have talked about a lot of information such as:To summarise the key points again,

・As per Japanese ordinances, water supply equipment and drainage equipment construction are basically not possible unless the designated business is a designated company.
・It may be accused of replacing the gasket or faucet, but be aware of the major risks.
・Even if you regret it, such as not being able to get insurance in the event of a problem, it may lead to a slow problem.
・If you are worried about DIY, it is best to first contact the waterworks bureau or management association and ask them to introduce you to a designated construction company.
・Even beginners can easily take on the prevention of freezing and simple inspections.
・If you are going to pass through the pipes without breaking the floor, there is a method that uses exposed pipes or attics, but this is also recommended to consult an expert.

You may be a little stubborn, but water equipment is one of the lifebloods of residential functions.If water leaks or hygiene problems are caused by impersonation, life will become extremely difficult, so we recommend taking careful action.

Ultimately, before trying DIY, ask yourself, "Is this really a minor task?" and see if it doesn't violate the laws and regulations or the management rules.If you still think it's necessary, you can end up asking a specialist who has insurance and after-sales service as much as possible, which will ultimately lead to peace of mind.

Self-renovation is a dreamy and fun, but the plumbing area is a place where problems are likely to occur.Prepare in a planned manner and make your home comfortable as long as it is not too difficult.We sincerely support you in order to ensure your DIY is safe and successful.

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(References and Videos) - "Water Utilization Act and Water Supply Ordinances of each local government"... Official website of water bureaus bureaus for city and town
・"Sewerage Act and Drainage Equipment Construction Guide"...Sewerage Department Web page for prefectures, cities, towns, and villages

That's all.Thank you for reading to the end.Enjoy creating a safe and comfortable home.

If you're wondering "How much renovation or remodeling can I actually do on my own home?" or "Where should I even start?", please visit this page. If you're looking to learn more about specific renovation processes or construction details, don't miss this page as well!